Abstract:
The present invention discloses a manufacturing method for an optical device having a solvate, comprising the following steps: providing a substrate, depositing a solute on the substrate, and placing the substrate in the vapor environment of a solvent such that the solvent and the solute on the substrate form a solvate exhibiting optical properties. Furthermore, the present invention provides an optical device having a solvate, which modulates the photoluminescence (PL) intensity of the optical device via the solvate. The optical device is obtained by means of the above-described manufacturing method.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    (a) Field of the Invention 
         [0002]    The present invention relates to an optical device and manufacturing method thereof, and more particularly to an optical device which modulates the photoluminescence (PL) intensity of the optical device via a solvate and manufacturing method thereof. 
         [0003]    (b) Description of the Prior Art 
         [0004]    A solvate is formed by the combination of solvent molecules with solute ions or molecules such that the crystallized crystal changes in its structure and thus has different physical properties, such as solubility, boiling point, melting point, optical properties and the like. Formerly, most of those who noted differences in the optical properties are from the pharmaceutical industry. Moreover, conventional solvates are mostly obtained by crystallization due to temperature fluctuations. A solute is dissolved in a solvent at a high temperature, and then the solute in the solution slowly crystallizes out as the temperature of the supersaturated solution is gradually lowered. During crystallization, the solvent and solute molecules sequentially arrange themselves in an orderly manner to form a crystallized crystal, i.e. a solvate. 
         [0005]    An OLED display is a display device that performs display by using the self-luminescent property of an organic luminescent material. It is mainly comprised of a pair of electrodes and an organic light-emitting layer. The organic light-emitting layer comprises a luminescent material. When an electrical current passes through the transparent anode and the metal cathode, electrons and holes recombine with each other in the luminescent material to generate excitons so that the luminescent material can emit light. However, there are still some problems that need to be overcome in organic electroluminescent devices, especially in the development of highly stable and efficient luminescent materials. 
         [0006]    Furthermore, with the development of solar cells, today there are numerous types of solar cells, typically, for example, monocrystalline silicon solar cells, poly-crystalline silicon solar cells, amorphous silicon solar cells, compound solar cells, dye-sensitized solar cells and the like. In order to reduce the cost, the active development of amorphous silicon thin film solar cells at present is the major trend, but the efficiency is still too low in practical use. 
       SUMMARY OF THE INVENTION 
       [0007]    In view of the above-described problems of the prior art, it is an object of the present invention to provide an optical device having a solvate and its manufacturing method. The optical device modulates the photoluminescence (PL) intensity of the optical device via the solvate so as to solve the problem of the development of luminescent materials for organic light-emitting diode devices and improve the efficiency of solar cells. 
         [0008]    It is a further object of the present invention to provide a solvate prepared by a crystallization process, and it is found from the measurement of optical properties that the solvate has significant influence on the PL. Moreover, to extend its applications, organic semiconductor materials commonly used in the semiconductor industry are particularly vapor deposited on substrates resulting in film deposition, and the films are exposed to a solvent vapor which permits the formation of solvates. Accordingly, it is discovered that the influence of a solvate causes a significant change in the PL measurement so as to modulate the PL intensity via the solvate. 
         [0009]    It is still a further object of the present invention to provide a manufacturing method for an optical device having a solvate, which comprises the steps of: providing a substrate, depositing a solute on the substrate, and placing the substrate in a vapor environment of a solvent such that the solvent and the solute on the substrate form a solvate exhibiting optical properties. The solute may be deposited on the substrate by a vapor deposition process. The temperature for the vapor environment of the solvent is 40-100° C. The selected substrate may be a transparent substrate, such as a glass substrate, a polymer substrate and the like. The solute may be an organic semiconductor material. Furthermore, the present invention provides an optical device having a solvate, which is obtained by means of the above-described manufacturing method. The optical device having a solvate may be an organic light-emitting diode or a solar cell. Moreover, the organic light-emitting diode and the solar cell comprise an organic light-emitting layer and a photosensitizer layer, respectively, and the solvate is formed thereon. 
         [0010]    Another object of the present invention is to provide an optical device having a solvate, comprising a substrate and a solvate disposed on the substrate. The solvate is prepared from an organic semiconductor material and an organic solvent, and exhibits optical properties. The substrate used may be a transparent substrate, such as a glass substrate, a polymer substrate, etc. The optical device having a solvate may be an organic light-emitting diode or a solar cell. The organic light-emitting diode further comprises an organic light-emitting layer. The solvate may be deposited on the organic light-emitting layer or doped thereinto. Moreover, the solar cell may further comprise a photosensitizer layer, and the solvate may be deposited on the photosensitizer layer or doped thereinto. 
         [0011]    As stated above, the present invention may have one or more of the following advantages: 
         [0012]    (1) In the present invention, the differences of solvates are examined from the viewpoint of optical properties and the concept of a solvate is introduced and will be a factor considered in manufacturing devices. Almost no prior art is directed to the influence of a solvate on the optical properties. Formerly, most of those who noted this subject are from the pharmaceutical industry, so it is a new attempt to introduce this concept to the device and semiconductor industries. 
         [0013]    (2) Conventional organic solvates are mostly obtained by crystallization due to temperature fluctuations. The present invention utilizes this concept to change the formation mechanism. Solute molecules are vapor deposited on a substrate and then exposed to an organic solvent vapor to obtain an organic solvate. Therefore, this method can be advantageously applied to thin-film elements. 
         [0014]    (3) The present invention utilizes the concept that an organic solvate change the optical properties of the organic compound. Optimization and control of the properties can be used to achieve an expected purpose whether in the optoelectronic or semiconductor industry, or even in the organic solar cell field. This breaks through the limitation that it is eager to seek or develop new materials while the problem of demand for new materials occurs. Also, the properties of materials can be altered by different manufacturing techniques so as to achieve a desired purpose. 
         [0015]    (4) The luminous intensity of a light-emitting diode can be modulated according to the present invention. 
         [0016]    (5) The concept of the present invention together with a solvate allows for an increase in the light absorption intensity of a solar cell. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is a schematic view of a preferred embodiment of the preparation of a solvate by a crystallization process according to the present invention; 
           [0018]      FIG. 2A  is a diagram showing a molecular structure of 1,1-bi-2-naphthol; 
           [0019]      FIG. 2B  is a diagram showing a molecular structure of tris-(8-hydroxyquinoline) aluminum(III); 
           [0020]      FIG. 3  is a flow chart of a preferred embodiment of a manufacturing method for an optical device having a solvate according to the present invention; 
           [0021]      FIG. 4  is a schematic view showing a process of step S 34  in  FIG. 3 ; 
           [0022]      FIG. 5  is a schematic view showing a structure of a first embodiment of an optical device having a solvate according to the present invention; 
           [0023]      FIG. 6  is a schematic view showing a structure of a second embodiment of an optical device having a solvate according to the present invention; 
           [0024]      FIG. 7  is a schematic view showing a structure of a third embodiment of an optical device having a solvate according to the present invention; and 
           [0025]      FIG. 8  is a schematic view showing a structure of a fourth embodiment of an optical device having a solvate according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0026]    Referring to  FIG. 1 , a flow chart of a preferred embodiment of the preparation of a solvate by a crystallization process according to the present invention is shown. The steps are as follows: step S 11 , putting 1,1-bi-2-naphthol (Binol, as shown in  FIG. 2A ) or tris-(8-hydroxyquinoline) aluminum(III) (Alq3, as shown in  FIG. 2B ) into a scintillating vial; step S 12 , immersing the vial in a constant temperature water bath set at 60-80° C.; step S 13 , slowly dropping the solvent into the vial using a micropipetter while shaking the vial to allow for homogeneous mixing of the solution, continuing to add the solvent into the solution to convert the cloudy solution into a clarified saturated solution; and step S 14 , lowering the temperature of the saturation solution from a high temperature to 25° C. and allowing generating crystalline solids due to the phenomenon that a high-temperature saturated solution would be supersaturated at a low temperature. In addition, the measurements which are performed on the resulted crystalline solid by using a thermogravimetric analyzer, a Fourier transform infrared spectrometer and powder X-ray diffraction to prove that the solvates do indeed exist. Next, in order to observe changes in the optical properties, a fluorescence spectrometer is used to measure the photoluminescence (PL) intensity and it is observed that the solvates cause significant changes in the PL intensity. For Binol, the solvates obtained from the solvents, dimethyl sulfoxide (DMSO) and N,N-dimethyl formamide (DMF) allow for an approximately 2-3 times increase in the PL intensity (as shown in Table 1); whereas the solvates obtained from Alq3 in DMF, nitrobenzene, chloroform or 1,4-dioxane reduce the PL intensity (as shown in Table 2). 
         [0000]    
       
         
               
               
               
               
             
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Excitation 
                 Emission 
                   
               
               
                   
                 wavelength 
                 wavelength 
                 PL intensity 
               
               
                   
                 (nm) 
                 (nm) 
                 (a.u.) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Binol powder 
                 290 
                 360 
                 176 
               
               
                 Binol which 
                 290 
                 376 
                 315 
               
               
                 crystallizes in DMSO 
               
               
                 Binol which 
                 290 
                 375 
                 510 
               
               
                 crystallizes in DMF 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
             
               
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Excitation 
                 Emission 
                   
               
               
                   
                 wavelength 
                 wavelength 
                 PL intensity 
               
               
                   
                 (nm) 
                 (nm) 
                 (a.u.) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Alq3 powder 
                 380 
                 503 
                 767 
               
               
                 Alq3 which 
                 380 
                 503 
                 501 
               
               
                 crystallizes in DMF 
               
               
                 Alq3 which 
                 380 
                 503 
                 597 
               
               
                 crystallizes in 
               
               
                 nitrobenzene 
               
               
                 Alq3 which 
                 380 
                 503 
                 63 
               
               
                 crystallizes in 
               
               
                 chloroform 
               
               
                 Alq3 which 
                 380 
                 503 
                 565 
               
               
                 crystallizes in 
               
               
                 1,4-dioxane 
               
               
                   
               
             
          
         
       
     
         [0027]    Referring to  FIG. 3 , a flow chart of a preferred embodiment of the preparation of a solvate by a crystallization process according to the present invention is shown. The preparation process is as follows. In step S 31 , the solid powder of an organic semiconductor material, Binol or Alq3, is filled in the bottom of a long tube. The long tube is then closely coupled to a stainless steel hollow carrier and is vertically placed into a thick aluminium plate having multiple holes, the interior of which is formed as a closed space. After a vacuum pump is connected to the top end of the carrier, the vacuum switch is turned on to maintain an evacuated state in the carrier. In step S 32 , the temperature of a heater is set to a specific value, and then the temperature at the bottom of the tube is measured and recorded by a thermocouple probe. Next, the tube is heated gradually to reach the sublimation point of Binol or Alq3, and at this time, a glass substrate placed in the carrier faces downward such that gas molecules of Binol or Alq3 deposit on the glass substrate to start film coating. In step S 33 , Binol or Alq3 continuously sublimates to gas such that a thin film begins to appear on the surface of the glass substrate, and the vapor deposition is performed for a period of about 30 minutes. Then the vacuum is released, and the film-coated glass substrate is taken out. Finally, a PL test is performed on the film-coated glass substrate. And in step S 34 , as shown in  FIG. 4 , a solvent is added into a vessel and the film-deposited glass substrate is then put thereinto. After sealed, the vessel is put into an oven at 50° C. lasting for several hours to allow sufficient contact between the solvent vapor and the film, and the solvent vapor molecules slowly evaporate and bring into contact with the film on the glass substrate resulting in the formation of a solvate so as to change its optical properties. Subsequently, the glass substrate is taken out for a PL test. Binol films are exposed to DMSO or DMF vapor, and Alq3 films are exposed to DMF, nitrobenzene, chloroform or 1,4-dioxane vapor. Comparing the PL spectra of the films exposed to the vapor with that of the unexposed films, it is discovered that the PL intensity of the films exposed to the vapor has changed, following the same trend as the solvates obtained by crystallization due to temperature fluctuations. In regard to the PL intensity of Binol films, the intensity of the vapor-treated films is approximately 5-10 times higher than that of the untreated films (as shown in Table 3). In regard to the PL intensity of Alq3 films, the intensity of the vapor-treated films is approximately ⅓-⅔ time that of the untreated films (as shown in Table 4). 
         [0000]    
       
         
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
                 TABLE 3 
               
               
                   
                   
               
               
                   
                 Excitation 
                 Emission 
                   
               
               
                   
                 wavelength 
                 wavelength 
                 PL intensity 
               
               
                   
                 (nm) 
                 (nm) 
                 (a.u.) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Binol film 
                 290 
                 360 
                 11 
               
               
                   
                 Binol film in 
                 290 
                 376 
                 155 
               
               
                   
                 DMSO vapor 
               
               
                   
                 Binol film in 
                 290 
                 375 
                 65 
               
               
                   
                 DMF vapor 
               
               
                   
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
             
               
               
               
               
             
           
               
                   
                 TABLE 4 
               
               
                   
                   
               
               
                   
                 Excitation 
                 Emission 
                   
               
               
                   
                 wavelength 
                 wavelength 
                 PL intensity 
               
               
                   
                 (nm) 
                 (nm) 
                 (a.u.) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Alq3 film 
                 380 
                 503 
                 323 
               
               
                 Alq3 film in 
                 380 
                 503 
                 153 
               
               
                 DMF vapor 
               
               
                 Alq3 film in 
                 380 
                 503 
                 228 
               
               
                 nitrobenzene vapor 
               
               
                 Alq3 film in 
                 380 
                 503 
                 109 
               
               
                 chloroform vapor 
               
               
                 Alq3 film in 
                 380 
                 503 
                 194 
               
               
                 1,4-dioxane vapor 
               
               
                   
               
             
          
         
       
     
         [0028]    Referring to  FIG. 5 , a schematic view showing a structure of a first embodiment of an optical device having a solvate according to the present invention is shown. In this figure, the optical device having a solvate is an organic light-emitting diode  5 , and it sequentially comprises, from bottom to top, a transparent substrate  51 , a transparent anode  52 , a hole transporting layer  53 , an organic light-emitting layer  54 , a solvate layer  55 , an electron transporting layer  56  and a metal cathode  57 . The solvate layer  55  is vapor deposited on the organic light-emitting layer  54  by means of the above-described method. The solvate layer  55  is formed from Binol and DMSO or DMF, or from Alq3 and DMF, nitrobenzene, chloroform or 1,4-dioxane. 
         [0029]    Referring to  FIG. 6 , a schematic view showing a structure of a second embodiment of an optical device having a solvate according to the present invention is shown. In this figure, the optical device having a solvate is a solar cell  6 , and it sequentially comprises, from bottom to top, a second transparent conductive substrate  61 , a titanium dioxide layer  62 , a photosensitizer layer  63 , a solvate layer  64 , an electrolyte layer  65 , a metal layer  66  and a first transparent conductive substrate  67 . The solvate layer  64  is vapor deposited on the photosensitizer layer  63  by means of the above-described method. The solvate layer  64  is formed from Binol and DMSO or DMF, or from Alq3 and DMF, nitrobenzene, chloroform or 1,4-dioxane. 
         [0030]    Referring to  FIG. 7 , a schematic view showing a structure of a third embodiment of an optical device having a solvate according to the present invention is shown. In this figure, the optical device having a solvate is an organic light-emitting diode  7 , and it sequentially comprises, from bottom to top, a transparent substrate  71 , a transparent anode  72 , a hole transporting layer  73 , an organic light-emitting layer  74 , an electron transporting layer  76  and a metal cathode  77 . The organic light-emitting layer  74  is a single-layer or multi-layer structure formed from a fluorescent luminescent material, a phosphorescent luminescent material or a combination thereof, further having a solvate  75  doped thereinto or coated thereon. Moreover, the solvate is prepared from an organic semiconductor material and an organic solvent, and exhibits optical properties. 
         [0031]    Referring to  FIG. 8 , a schematic view showing a structure of a fourth embodiment of an optical device having a solvate according to the present invention is shown. In this figure, the optical device having a solvate is a solar cell  8 , and it sequentially comprises, from bottom to top, a second transparent conductive substrate  81 , a titanium dioxide layer  82 , a photosensitizer layer  83 , an electrolyte layer  85 , a metal layer  86  and a first transparent conductive substrate  87 . The photosensitizer layer  83  further has the solvate  84  doped thereinto or deposited thereon. Moreover, the solvate is prepared from an organic semiconductor material and an organic solvent, and exhibits optical properties. 
         [0032]    The above description is illustrative only and is not to be considered limiting. Various modifications or changes can be made without departing from the spirit and scope of the invention. All such equivalent modifications and changes shall be comprised within the scope of the appended claims.