Patent Publication Number: US-2013247968-A1

Title: Photoelectric device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to and the benefit of U.S. Provisional Application No. 61/613,470, filed on Mar. 20, 2012, in the USPTO, the disclosure of which is incorporated herein in its entirety by reference. 
    
    
     BACKGROUND 
     1. Field 
     One or more embodiments of the present invention relate to a photoelectric device. 
     2. Description of Related Art 
     Photoelectric conversion devices that convert light energy to electric energy, and solar cells using sun light to generate electric energy, have drawn much attention as energy sources that can replace fossil fuel. 
     Solar cells using various driving principles have been studied, and dye sensitized solar cells, which have a very high photoelectric conversion efficiency when compared to conventional solar cells, are being considered as next-generation solar cells. 
     The dye sensitized solar cells include a photosensitive dye that receives incident light having one or more wavelengths in the visible spectrum to generate excited electrons from the incident light, a semiconductor material capable of receiving the excited electrons, and an electrolyte capable of reacting with electrons that returns after passing through an external circuit. 
     SUMMARY 
     One or more embodiments of the present invention include a photoelectric device for which materials and manufacturing costs may be reduced, and also, for which loss due to electrical resistance may be reduced. 
     According to one or more embodiments of the present invention, there is provided a photoelectric device including first and second substrates facing each other, a separator between the first and second substrates and having a plurality of openings such that opposite first and second surfaces of the separator are fluidly connected to each other, and first and second electrodes on the first and second surfaces of the separator, respectively, wherein the first and second electrodes are fluidly connected to the openings of the separator. 
     The first and second electrodes may each have openings. 
     The openings of the first and second electrodes may be aligned with the openings of the separator. 
     The first and second electrodes may each include a metal plate. 
     The first and second electrodes may each include titanium. 
     The photoelectric device may further include a light-absorbing layer on the first electrode, and a catalyst layer on the second electrode. 
     The light-absorbing layer may be on a surface of the first electrode facing the first substrate, and the catalyst layer may be on a surface of the second electrode facing the second substrate. 
     The first and second electrodes, the light-absorbing layer, and the catalyst layer may each have openings that are fluidly connected to the openings of the separator. 
     The openings of the separator may have a generally regular pattern. 
     At least a portion of the separator may be porous. 
     The photoelectric device may further include an electrolyte between and directly contacting the first and second substrates. 
     The separator may include an insulating material to electrically insulate the first and second electrodes from each other. 
     The separator may include at least one of a non-conductive resin material or a porous inorganic material. 
     The separator may include at least one of polytetrafluoroethylene, a vinyl resin, a silicon (Si) oxide, or a zirconium (Zr) oxide. 
     The photoelectric device may further include a first spacer between the first substrate and the separator, and a second spacer between the second substrate and the separator. 
     The photoelectric device may have first and second accommodation spaces that are proximate the first and second spacers, respectively, and that are fluidly connected to each other via the openings in the separator. 
     The photoelectric device may further include a plurality of first spacers on different portions at a first side of the separator, and a plurality of second spacers on different portions at a second side of the separator. 
     The photoelectric device may further include a plurality of first and second spacers between the separator and the first and second substrates, respectively, and the separator may be spaced from the first and second substrates. 
     The first spacer may include a transparent material, and the first substrate may be configured to receive light. 
     The photoelectric device may further include a sealing member between the first and second substrates and spaced from the separator. 
     As described above, according to the one or more embodiments of the present invention, a light-absorbing layer is located in front of an electrode structure along a path of light, and thus, an electrode may be formed using a metal having excellent electric conductivity without having to consider light transparency of the electrode structure. Accordingly, compared to a structure in which an electrode is formed of a transparent conducting layer having both optical transparency and electrical conductivity, costs for materials and special processes may be reduced. In addition, by forming an electrode using a metal having higher electric conductivity than a transparent conducting layer, resistance loss in a photocurrent may be reduced and a high photoelectric conversion efficiency may be obtained. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a disassembled perspective view of a photoelectric device according to an embodiment of the present invention; 
         FIG. 2  is a cross-sectional view of the photoelectric device of the embodiment shown in  FIG. 1  cut along the line II-II; 
         FIG. 3  is an expanded view of a portion of the photoelectric device of embodiment shown in  FIG. 2 ; 
         FIG. 4  is a disassembled perspective view of a portion of the photoelectric device of the embodiment shown in  FIG. 1 ; 
         FIGS. 5A through 5D  are views for illustrating formation of openings of a second electrode according to an embodiment of the present invention; 
         FIGS. 6A and 6B  are views for illustrating formation of openings of first and second electrodes and a separator according to an embodiment of the present invention; 
         FIG. 7  is a plan view of a separator according to another embodiment of the present invention; 
         FIG. 8  is a cross-sectional view of a photoelectric device according to a comparative example; 
         FIG. 9  is a disassembled perspective view of a photoelectric device according to another embodiment of the present invention; 
         FIG. 10  is a cross-sectional view of the photoelectric device cut along the line X-X of  FIG. 9 ; and 
         FIG. 11  is an expanded view of a portion of the photoelectric device of the embodiment shown in  FIG. 10 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a disassembled perspective view of a photoelectric device according to an embodiment of the present invention.  FIG. 2  is a cross-sectional view of the photoelectric device of the embodiment shown in  FIG. 1  cut along the line II-II.  FIG. 3  is an expanded view of a portion of the photoelectric device of the embodiment shown in  FIG. 2 . 
     Referring to  FIGS. 1 ,  2 , and  3 , the photoelectric device includes: first and second substrates  110  and  120 ; a separator  150  between the first and second substrates  110  and  120  and including a plurality of openings  150 ′ formed so that first and second surfaces  150   a  and  150   b  are fluidally coupled to each to other; and first and second electrodes  111  and  121 . In addition, a plurality of openings  111 ′ and  121 ′ that are fluidally coupled to the openings  150 ′ of the separator  150  may be formed in the first and second electrodes  111  and  121 . 
     The first substrate  110  may be a light-receiving surface for receiving incident light, and may be formed of a highly light-transmissive material. For example, the first substrate  110  may be formed of a glass substrate or a resin substrate. A resin substrate usually has flexibility, and is thus suitable for uses where flexibility is desired. 
     The second substrate  120  is not particularly limited as long as it may accommodate an electrolyte  170 , and may be formed of, for example, a glass substrate or a resin substrate. The second substrate  120  may face the first substrate  110  while having the separator  150  therebetween. For example, the second substrate  120  may be coupled to the first substrate  110  using a sealing member  180 , which may be located along edges of the first and second substrates  110  and  120 , wherein the sealing member  180  surrounds the electrolyte  170  filled between the first and second substrates  110  and  120  to encapsulate the photoelectric device, thereby protecting the photoelectric device from external environments. 
     As illustrated in  FIGS. 2 and 3 , the electrolyte  170  is filled between the first and second substrates  110  and  120 , which may directly contact the electrolyte  170 . Electrodes located at two ends form a current path of the photoelectric device, that is, first and second electrodes  111  and  121  are formed on the separator  150 , but are not formed on the first and second substrate  110  and  120 . The first and second substrates  110  and  120  excluding the above-described electrode structure may directly contact the electrolyte  170 . 
     The separator  150  physically separates the first and second electrodes  111  and  121 , which have opposite polarities, and electrically insulates the first and second electrodes  111  and  121  from each other, thereby preventing or reducing the likelihood of a short circuit due to contact between the first and second electrodes  111  and  121 . The separator  150  allows transportation of electrons (e) (see  FIG. 3 ) according to an electrical field between the first and second electrodes  111  and  121 , and allows transmission of the electrolyte  170 , through which electrons (e) are transferred, and/or allows transmission of iodine ions in the electrolyte  170 . 
     The separator  150  may be formed of an electrically insulating material, and may include a plurality of openings  150 ′ to allow transmission of the electrolyte  170  or transmission of ions in the electrolyte  170 . The first and second surfaces  150   a  and  150   b  of the separator  150  are fluidally coupled to each other via the openings  150 ′. What is meant by “the first and second surfaces  150   a  and  150   b  of the separator  150  being fluidally coupled to each other” is that the electrolyte  170 , through which electrons (e) or ions in the electrolyte (e.g., electrolyte  170 ) are transferred, enables the electrons (e) or ions to pass through the separator  150 , and that a current path may be formed through the separator  150  between the first electrode  111  and the second electrode  121 . 
     The separator  150  may be formed of a material that has electrical insulation properties, that has little reactivity with respect to the electrolyte  170  in a high-temperature operating environment (e.g., reaching  85  degrees), and that has a stable chemical stability with respect to the electrolyte  170 . For example, the separator  150  may be formed of a non-conductive resin material such as polytetrafluoroethylene (e.g., TEFLON®, which is a registered trademark of E. I. du Pont de Nemours and Company, Wilmington Del.), or a vinyl resin. 
     The openings  150 ′ of the separator  150  may be formed by processing a planar raw material by perforation, such as by punching, stamping, or molding of a resin material. For example, the separator  150  may be formed of a non-conductive resin material, and a plurality of openings  150 ′ may be formed by molding a non-conductive resin material. 
     As long as the openings  150 ′ of the separator  150  are fluidally coupled, the forms of the openings  150 ′ of the present embodiment are not limited. As illustrated in  FIG. 1 , the openings  150 ′ may be patterned in the separator  150 . For example, the openings  150 ′ may be formed by patterning generally at uniform positions (e.g., a generally uniform pattern), and as illustrated in  FIG. 1 , the openings  150 ′ may be arranged in matrix patterns along first and second directions, such as a row direction (x-direction) and a column direction (y-direction). 
     When forming patterns of the openings  150 ′, the openings  150 ′ may be distributed over substantially the entire surface area of the separator  150  (e.g., the first and second surfaces  150   a  and  150   b ) with a uniform density so that the electrolyte  170 , through which electrons (e) are transported, may be uniformly transmitted. In an area with a low degree of transmission of the electrolyte  170 , a path resistance of electron transportation increases, and thus, photoelectric efficiency is decreased. Accordingly, the openings  150 ′ may be distributed over the entire area of the separator  150  at a uniform density. 
     The forms of the openings  150 ′ may be variously formed in consideration of a flow resistance of the electrolyte  170 , of workability in regard to perforation, and of mechanical intensity of the separator  150 , and as illustrated in  FIG. 1 , the openings  150 ′ may have an approximately circular shape, or a polygonal shape, such as a square. 
     The first and second electrodes  111  and  121  having opposite polarities are arranged on the first and second surfaces  150   a  and  150   b  of the separator  150 , respectively. The first and second electrodes  111  and  121  may face each other with the separator  150  therebetween, and may have planar shapes over substantially the entire surface areas of the first and second surfaces  150   a  and  150   b  of the separator  150 . 
     The first electrode  111  may be formed as a negative electrode of the photoelectric device, for example, which withdraws light-generated carriers such as electrons. The second electrode  121  may be formed as an electrode having an opposite polarity to that of the first electrode  111 , for example, as a positive electrode, and may accommodate, for example, a flow of electrons that have passed through an external circuit (not shown) and may supply the same to the first electrode  111 . 
     The first and second electrodes  111  and  121  may be formed of a metal having excellent electric conductivity, having little reactivity with respect to the electrolyte  170  in a high-temperature operating environment (e.g., reaching about 85 degrees), and/or being chemically stable with respect to the electrolyte  170  (e.g., titanium). For example, the first and second electrodes  111  and  121  may be a thin film plate covering substantially the entire surface area of the first and second surfaces  150   a  and  150   b , such as a titanium thin film plate. 
     A light-absorbing layer  115  may be formed on the first electrode  111 , may be electrically coupled to the first electrode  111 , and may form a conductive contact with the first electrode  111 . The light-absorbing layer  115  may absorb light (L) incident through the first substrate  110  to generate light carriers such as, for example, electrons. The light-absorbing layer  115  may be formed on a surface of the first electrode  111  facing the first substrate  110  so as to absorb as much light (L) as possible. 
     For example, the light-absorbing layer  115  may include a semiconductor layer to which a photosensitive dye is adsorbed. For example, the semiconductor layer may be formed of an oxide of a metal such as Cd, Zn, In, Pb, Mo, W, Sb, Ti, Ag, Mn, Sn, Zr, Sr, Ga, Si, or Cr. 
     For example, the photosensitive dye may be formed of molecules that absorb light in a visible ray band and cause fast electron transportation from a light-excited state to a semiconductor layer. For example, the photosensitive dye may be a ruthenium-based photosensitive dye. 
     A catalyst layer  125  may be formed on the second electrode  121 , may be electrically coupled to the second electrode  121 , and may form a conductive contact with the second electrode  121 . For example, the catalyst layer  125  may function as a reduction catalyst with respect to the electrolyte  170 , and may function as a reduction catalyst for receiving electrons provided via the second electrode  121  and for reducing the electrolyte  170 , and may ultimately reduce the light-absorbing layer  115 , which is oxidized according to withdrawal of light-generated electrons, again. For example, the catalyst layer  125  may be formed on a surface of the second electrode  121  facing the second substrate  120  to form a broad contact surface with the electrolyte  170 . 
     The catalyst layer  125  may be formed of a material having a catalyzed reduction function for providing electrons to the electrolyte  170 , and may be formed of, for example, a metal such as platinum (Pt), gold (Ag), silver (Au), copper (Cu), aluminum (Al), a metal oxide such as a tin oxide, and/or a carbonaceous material such as graphite. 
     In order to allow transmission of the electrolyte  170 , a plurality of openings  111 ′ and  121 ′ may be formed in the first and second electrodes  111  and  121 , and the openings  111 ′ and  121 ′ of the first and second electrodes  111  and  121  may be fluidally coupled to the openings  150 ′ of the separator  150 , thereby forming a path of the electrolyte  170  through which electrons are transported. 
     Referring to  FIG. 1 , a plurality of openings  111 ′ may be formed in the first electrode  111  and the light-absorbing layer  115  formed on the first surface  150   a  of the separator  150  to allow transmission of the electrolyte  170 . For example, the openings  111 ′ of the first electrode  111  and the light-absorbing layer  115  may be aligned. While the openings  111 ′ of the first electrode  111  and the light-absorbing layer  115  are denoted by the same reference numeral, this is for convenience of understanding, and the openings  111 ′ of the first electrodes  111  and the light-absorbing layer  115  are not necessarily aligned, according to various embodiments of the present invention. 
     Similarly, a plurality of openings  121 ′ may be formed in the second electrode  121  and the catalyst layer  125  formed on the second surface  150   b  of the separator  150  to allow transmission of the electrode  170 . For example, the openings  121 ′ of the first electrode  121  and the catalyst layer  125  may be aligned. While the openings  121 ′ of the first electrode  121  and the catalyst layer  125  are denoted by the same reference numeral, this is for convenience of understanding, and the openings  121 ′ of the first electrodes  121  and the catalyst layer  125  are not necessarily aligned according to various embodiments of the present invention. 
     The openings  111 ′ and  121 ′ of the first and second electrodes  111  and  121  may form a path of the electrolyte  170  coupled to the openings  150 ′ of the separator  150 . By forming a path of the electrode layer  170  that is fluidally coupled from the catalyst layer  125  to the light-absorbing layer  115  in a thickness direction of the separator  150 , a path for reduction electrons may be formed from the catalyst layer  125  to the light-absorbing layer  115  through the medium of the electrolyte  170 . 
     According to the embodiment of the invention shown in  FIG. 1 , the openings  150 ′ of the separator  150  and the openings  111 ′ and  121 ′ of the first and second electrodes  111  and  121  are aligned with each other, and are continuously extended in a thickness direction, although the present invention is not limited thereto. For example, the openings  150 ′ of the separator  150  and the openings  111 ′ and  121 ′ of the first and second electrodes  111  and  121  may be offset from each other as long as they are fluidally coupled to each other to form a path of the electrolyte  170 . 
     A first spacer  161  is located between the first substrate  110  and the separator  150 , and may thereby form a first accommodation space S 1  between the first substrate  110  and the separator  150 . Also, a second spacer  162  is located between the second substrate  120  and the separator  150 , and may thereby form a second accommodation space S 2  between the second substrate  120  and the separator  150 . The first and second accommodation spaces S 1  and S 2  are fluidally coupled to each other via the openings  111 ′,  150 ′, and  121 ′ of the separator  150  and the first and second electrodes  111  and  121 . 
     The first and second accommodation spaces S 1  and S 2  and the openings  111 ′,  150 ′, and  121 ′ coupling the spaces S 1  and S 2  are filled with the electrolyte  170 , and a current path between the first electrode  111  (or the light-absorbing layer  115 ) in the first accommodation space S 1  and the second electrode  121  (or the catalyst layer  125 ) in the second accommodation space S 2  may be formed via the electrolyte  170 . 
     Referring to  FIG. 3 , heights h 1  and h 2  of the first and second spacers  161  and  162  correspond to a volume of the first accommodation space S 1  between the first substrate  110  and the separator  150 , and to a volume of the second accommodation space S 2  between the second substrate  120  and the separator  150 , respectively. For example, by adjusting the heights h 1  and h 2  of the first and second spacers  161  and  162 , volumes of the first and second accommodation spaces S 1  and S 2  may be controlled (e.g., changed or adjusted), and the amount of the electrolyte  170  stored in the first and second accommodation spaces S 1  and S 2  may be increased or decreased. According to the current embodiment, the heights h 1  and h 2  of the first and second spacers  161  and  162  may be approximately the same, but the present invention is not limited thereto. 
       FIG. 4  is a disassembled perspective view of a portion of the photoelectric device of  FIG. 1 . Referring to  FIG. 4 , the separator  150  between the first and second substrates  110  and  120  is spaced from the first and second substrate  110  and  120 . The separator  150  may be supported by the first and second spacers  161  and  162  via different surfaces, respectively. That is, the first and second surfaces  150   a  and  150   b  are respectively supported by the first and second spacers  161  and  162 . To firmly fix the separator  150  and to maintain the first and second accommodation spaces S 1  and S 2  at uniform intervals, a plurality of the first and second spacers  161  and  162  may be included. For example, the first and second spacers  161  and  162  may face each other by interposing the separator  150  therebetween. 
     A plurality of first spacers  161  may be located on different positions between the first substrate  110  and the light-absorbing layer  115 , and a plurality of second spacers  162  may be located on different positions between the second substrate  120  and the catalyst layer  125 . 
     The arrangement, number, and shape of the first and second spacers  161  and  162  are not as illustrated in  FIG. 4  but may vary as long as they respectively form the first and second accommodation spaces S 1  and S 2  between the first and second substrates  110  and  120  and the separator  150 . For example, referring to  FIG. 4 , the first and second spacers  161  and  162  have column forms that are individually isolated. 
     Alternatively, the first and second spacers  161  and  162  may be, for example striped patterned spacers extended in a direction (e.g., a predetermined direction), or sheet-type spacers in a mesh pattern. 
     The first spacer  161  may be formed between the first substrate  110  and the light-absorbing layer  115 . When the first spacer  161  is formed of a material having a high light transitivity, light loss of the light absorption layer  115  may be reduced, and thus, the first spacer  161  may be formed of glass frit or a transparent resin material. 
     The first and second spacers  161  and  162  may be formed of a material that may adhere to (and between) the corresponding first and second substrates  110  and  120  and the separator  150  according to heat curing, laser irradiation, or the like; for example, the first and second spacers  161  and  162  may be formed of a glass frit, an organic resin, or a hot melt resin. 
       FIGS. 5A through 5D  are views for explaining formation of the openings  121 ′ of the second electrode  121  according to an embodiment of the present invention. As illustrated in  FIGS. 5A and 5B , the catalyst layer  125  is stacked on the second electrode  121  to form a raw material substrate. For example, a layer forming process, such as sputtering or printing, may be applied to the second electrode  121  to form the catalyst layer  125 . 
     Next, as illustrated in  FIGS. 5C and 5D , the raw material substrate is perforated to form a plurality of openings  121 ′. For perforation of the raw material substrate, punching or stamping may be applied. 
     For example, the raw material substrate may be placed on a worktable (D) and pressed using a press (P) to perforate the catalyst layer  125  and the second electrode  121 , and the openings  121 ′ of the catalyst layer  125  and the second electrode  121  may be aligned. 
     Meanwhile, similar to  FIGS. 5A through 5D , the same operations may form the openings  111 ′ of the first electrode  111 . That is, the light-absorbing layer  115  may be stacked on the first electrode  111  to form a raw material substrate, and the raw material substrate may perforate the light-absorbing layer  115  and the first electrode  111 , and the openings  111 ′ of the light-absorbing layer  115  and the first electrode  111  may be aligned. 
     However, the embodiments of the present invention are not limited thereto, and, for example, the first electrode  111  may be perforated to form a plurality of openings  111 ′, and then the light-absorbing layer  115  may be patterned to correspond to patterns of the openings  111 ′ of the first electrode  111 . 
       FIGS. 6A and 6B  are views for explaining formation of the openings  111 ′,  150 ′, and  121 ′ of the separator  150  and the first and second electrodes  111  and  121  according to an embodiment of the present invention. Referring to  FIGS. 6A and 6B , the first electrode  111  and the light-absorbing layer  115  are stacked on the first surface  150   a  of the separator  150 , and the second electrode  121  and the catalyst layer  125  are stacked on the second surface  150   b  of the separator  150 , thereby forming a raw material substrate. Then, the raw material substrate may be perforated. For perforation of the raw material substrate, punching or stamping may be applied. 
     For example, the raw material substrate may be placed on a worktable (D) and pressed using a press (P) to thereby perforate the first and second electrodes  111  and  121  and the separator  150 , and the openings  111 ′,  150 ′, and  121 ′ of the first and second electrodes  111  and  121  and the separator  150  may be aligned. 
       FIG. 7  is a plan view of a separator  250  according to another embodiment of the present invention. Referring to  FIG. 7 , a plurality of openings  250 ′ are arranged in the separator  250  in alternate patterns; for example, a row of openings  250 ′ may be arranged in alternating positions with respect to an adjacent row of openings  250 ′, or a column of openings  250 ′ might not be aligned with an adjacent column of openings  250 ′. According to this pattern of the openings  250 ′, transmission of the electrolyte  170  may be uniformly conducted over the entire area of the separator  250 . Alternatively, the openings  250 ′ of the separator  250  may be arranged, for example, at irregular positions instead of at regular positions in regular patterns. 
       FIG. 8  is a cross-sectional view of a photoelectric device according to a comparative example. Referring to  FIG. 8 , the photoelectric device includes first and second substrate  10  and  20 , and first and second electrodes  11  and  21  respectively formed on the first and second substrate  10  and  20 . The photoelectric device includes a light-absorbing layer  15  formed on the first electrode  11 , and a catalyst layer  25  formed on the second electrode  21 . 
     Light that has transmitted through the first electrode  11  is absorbed by the light-absorbing layer  15 , and electrons are generated through excitation of the light-absorbing layer  15 . The first electrode  11  is formed of a material having electrical conductivity and also optical transparency so as to allow light transmission. For example, the first electrode  11  may be formed of a transparent conducting oxide (TCO) such as indium tin oxide (ITO), fluorine tin oxide (FTO), or antimony tin oxide (ATO). To form a transparent conductive layer, expensive materials and special layer forming processes are required, and this increases the manufacturing costs of the photoelectric device. In addition, due to the characteristics of the material of the transparent conductive layer, the transparent conductive layer has low electrical conductivity, which increases electrical resistance of a photocurrent. 
     Meanwhile, the second electrode  21  is formed on the second substrate  20 , and in consideration of adhering characteristics with respect to the second substrate  20 , which is a glass substrate, the second electrode  21  is also formed of a transparent conductive layer. As a result, according to the comparative example, transparent conductive layers are used to a wide extent as the first and second electrodes  11  and  21 , and thus, the manufacturing costs are increased, and due to the decreased conductive characteristics compared to metals, resistance loss is generated. 
     According to the embodiment of  FIG. 1 , the light-absorbing layer  115  is formed in front of the first electrode  111  along a direction of light incidence, and thus, the first electrode  111  may be formed of, for example, an opaque metal. That is, as the first electrode  111  and the light-absorbing layer  115  are sequentially formed on the separator  150 , the first electrode  111  may be excluded from a path of incidence of the light-absorbing layer  115 , and the first electrode  111  may be formed of an opaque metal. By forming the first electrode  111  using a metal instead of a transparent conductive layer, manufacturing costs of the photoelectric device may be reduced, and loss due to electrical resistance may also be reduced. 
     The second electrode  121  is formed on the second surface  150   b  of the separator  150 , and thus, there is no need to consider adhering characteristics of the second electrode  121  with the second substrate  120 . Accordingly, the second electrode  121  may be formed of a metal having excellent electrical conductivity. By forming the second electrode  121  using a metal instead of a transparent conductive layer, manufacturing costs of the photoelectric device may be reduced, and loss due to electrical resistance may also be reduced. 
       FIG. 9  is a disassembled perspective view of a photoelectric device according to another embodiment of the present invention.  FIG. 10  is a cross-sectional view of the photoelectric device of the embodiment shown in  FIG. 9  and cut along the line X-X of  FIG. 9 .  FIG. 11  is an expanded view of a portion of the photoelectric device of the embodiment shown in  FIG. 10 . 
     Referring to  FIGS. 9 through 11 , the photoelectric device includes first and second substrates  310  and  320  facing each other, and a separator  350  between the first and second substrates  310  and  320  and including a plurality of openings  350 ′ that are formed so that opposite first and second surfaces  350   a  and  350   b  of the separator  350  are fluidally coupled. In addition, the photoelectric device includes first and second electrodes  311  and  321  that are formed on the first and second surfaces  350   a  and  350   b  of the separator  350 , respectively. 
     The separator  350  physically separates the first and second electrodes  311  and  321  of different polarities, and electrically insulates the first and second electrodes  311  and  321  from each other, thereby preventing or reducing the likelihood of a short circuit due to contact between the first and second electrodes  311  and  321 . The separator  350  allows transportation of electrons (e) according to an electrical field between the first and second electrodes  311  and  321 , and, for example, transmission of the electrolyte  370 , through which electrons (e) are transferred. 
     The separator  350  may be formed of an electrical insulation material, and may have a porous structure in which a plurality of openings  350 ′ are formed so that the electrolyte  370  may transmit therethrough. For example, the separator  350  may be formed of a porous inorganic material. 
     When the separator  350  has a porous structure, a plurality of openings  350 ′ arranged on a two-dimensional plane, or a plurality of openings  350 ′ arranged three-dimensionally, may be included. For example, the separator  350  may include a silicon (Si) oxide or a zirconium (Zr) oxide; for example, the separator  350  may have a structure in which a plurality of oxide particles are adhered to one another while having pores interposed therebetween, or the separator  350  may be an inorganic thin layer that is formed on a sponge-shaped carrier substrate (not shown) including a plurality of pores. The pores between the plurality of oxide particles or the pores of the carrier substrate correspond to the openings  350 ′ that allow transmission of the electrolyte  370 . Also, the separator  350  may be formed as a membrane in which a plurality of pores are arranged two-dimensionally, and the plurality of pores may correspond to the openings  350 ′ that allow transmission of the electrolyte  370 . 
     When the separator  350  has a porous structure, this porous structure includes openings  350 ′ of both relatively fine scales and coarse scales. For example, the porous structure of the separator  350  may be formed by performing a mechanical forming operation, such as punching or stamping a planar raw material, or by performing various porous processes, such as sintering of micro-scale particles. 
     The first and second electrodes  311  and  321  of opposite polarities are formed on the first and second surfaces  350   a  and  350   b  of the separator  350 , respectively. The first and second electrodes  311  and  321  may be formed of a metal having excellent electrical conductivity, and may be formed as a metal thin plate over the entire surface areas on the first and second surfaces  350   a  and  350   b . For example, the first and second electrodes  311  and  321  may include titanium thin plates. 
     According to the present embodiment, as the first and second electrodes  311  and  321  are formed of a metal, costs for transparent conductive layers may be reduced, and loss from resistance due to the first and second electrodes  311  and  321  may be reduced. In detail, by placing a light-absorbing layer  315  in front of the first electrode  311  in a direction of incidence of light (L), optical transparency of the first electrode  311  is not to be considered. Accordingly, the first electrode  311  may be formed of a metal instead of a transparent conductive layer, thereby reducing loss caused by resistance. 
     The light-absorbing layer  315  may be formed on the first electrode  311 . The light-absorbing layer  315  may be formed on a surface of the first electrode  311  facing the first substrate  310  so that as much light (L) as possible may be absorbed by the light-absorbing layer  315 . A catalyst layer  325  may be formed on the second electrode  320 . To form a broad contact surface area with the electrolyte  370 , the catalyst layer  325  may be formed on a surface of the second electrode  321  facing the second substrate  320 . 
     A plurality of openings  311 ′ and  321 ′ may be formed in the first and second electrodes  311  and  321  to allow transmission of the electrolyte  370 , and the openings  311 ′ and  321 ′ of the first and second electrodes  311  and  321  may be fluidally coupled to the openings  350 ′ of the separator  350  to form a path of the electrolyte  370 , through which electrons (e) are transported. By forming a path of the electrolyte  370  that is fluidally coupled from the catalyst layer  325  to the light-absorbing layer  315  in a thickness direction of the separator  350 , transportation of electrons (e) may be conducted through the electrolyte  370 . 
     A first spacer  361  is located between the first substrate  310  and the separator  350 , and may enable a first accommodation space S 1  between the first substrate  310  and the separator  350 . Also, a second spacer  362  is located between the second substrate  320  and the separator  350 , and may enable a second accommodation space S 2  between the second substrate  320  and the separator  350 . The first and second accommodation spaces S 1  and S 2  are fluidally coupled to each other via the openings  311 ′,  350 ′, and  321 ′ of the separator  350  and the first and second electrodes  311  and  321 . 
     The first and second spacers  361  and  362  may respectively support the first and second surfaces  350   a  and  350   b  of the separator  350 , and may fix the separator  350  in a position separated from the first and second substrates  310  and  320 . To firmly fix the separator  350 , and also to maintain the first and second accommodation spaces S 1  and S 2  at uniform intervals, a plurality of the first and second spacers  361  and  362  may be included. 
     As illustrated in  FIG. 9 , the first and second spacers  361  and  362  may be striped patterned spacers extended in a direction (e.g., a predetermined direction or a y-direction). For example, the first spacer  361  may extend between adjacent rows of openings  311 ′ in the first electrode  311  (e.g., a predetermined direction or the y-direction). Also, the second spacer  362  may extend between adjacent rows of openings  321 ′ in the second electrode  321  (e.g., a predetermined direction or the y-direction). 
     A flow path (not shown) having a ruptured form may be formed in the first and second spacers  361  and  362 , and flow of the electrolyte  370  may be allowed through the flow path. The structure of the flow path described above is provided in order to increase photoelectric conversion efficiency of predetermined areas due to accumulation of the electrolyte  370 . 
     Meanwhile, a sealing member  380  may be located along edges of the first and second substrates  310  and  320 . By coupling the first and second substrates  310  and  320  by interposing the sealing member  380  therebetween, the first and second accommodation spaces S 1  and S 2  accommodating the electrolyte  370  may be encapsulated. 
     It should be understood that the described exemplary embodiments of the present invention should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments. While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, and their equivalents. 
     
       
         
           
               
             
               
                   
               
               
                 Description of Some of the Reference Characters 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                 110, 310: first substrate 
                 111, 311: first electrode 
               
               
                 111′,311′: opening of first electrode and  
                   
               
               
                 light-absorbing layer 
                   
               
               
                 121′,321′: opening of second electrode  
                   
               
               
                 and catalyst layer 
                   
               
               
                 115, 315: light-absorbing layer  
                 120, 320: second substrate 
               
               
                 121, 321: second electrode 
                 150, 250, 350 : separator 
               
               
                 150′, 250′, 350′: opening of the separator 
                 125, 325: catalyst layer 
               
               
                 150a, 350a : first surface of separator 
                   
               
               
                 150b, 350b : second surface of separator 
                   
               
               
                 161, 361: first spacer 
                 162, 362: second spacer 
               
               
                 170, 370: electrolyte 
                 180, 380: sealing member 
               
               
                 S1: first accommodation space 
                 S2: second accommodation space 
               
               
                 h1: height of first spacer 
                 h2: height of second spacer 
               
               
                 e: electron