Query: CsPbI3

title: Ultra stable Tb3+ CsPbI3 nanocrystal glasses for wide range high sensitivity optical temperature sensing
abstract: In this work, a series of perovskite nanocrystals glasses with different concentrations of Tb3+ doped CsPbI3, which have excellent characteristics in terms of water resistance and cyclic thermal stability, were prepared by melt quenching and in situ crystallization methods. With the introduction of Tb3+ the photoluminescence quantum yield of CsPbI3 was greatly improved. Considering that the two fluorescence peaks of Tb3+ and CsPbI3 at different positions respond differently to temperature stimuli, we studied the potential application of those glasses as optical temperature detection tools in the temperature range of 80 480 K. More importantly, the results showed higher sensitivity than other tools, with the maximum absolute and relative temperature sensitivities reaching as high as 0.034 K 1 and 1.78 K 1, respectively. This work is expected to provide an effective method for the application of CsPbX3 in high performance optical temperature sensing materials.

title: Unveiling the light soaking effects of the CsPbI3 perovskite solar cells
abstract: Pure inorganic perovskite of CsPbI3 attracts great attentions due to its excellent thermal stability and more suitable bandgap for tandem solar cells. The power conversion efficiency (PCE) of CsPbI3 perovskite solar cells has swiftly increased to 19.03% However, extensive researches on the material property and photovoltaic characterization are rather rare in the literatures. In this study, a remarkable light soaking effect is found in the CsPbI3 based perovskite solar cells as the PCE increases from 10.8% to 18.3% after 180 s soaking under AM 1.5G sunlight. Mechanisms behind this reproducible soaking effect have also been studied. It reveals that the depressed dark current caused by a stronger built in field and the decreased defects density passivated by the photogenerated electrons result in the enhanced PCE after light soaking. Moreover, we carefully characterize that the supposed "HPbI3" should be "DMAPbI3" synthesized through anti solvent vapor recrystallisation method.

title: Tuning the Surface Passivating Ligand Anchoring Position Enables Phase Robustness in CsPbI3 Perovskite Quantum Dot Solar Cells
abstract: Cubic CsPbI3 perovskite quantum dots (PQDs) with ideal optoelectronic properties are promising materials for solution processed photovoltaics. However, their phase stability suffers from the weakly.

title: Beach Chair Shaped Energy Band Alignment for High Performance b CsPbI3 Solar Cells
abstract: CsPbI3 perovskite has drawn worldwide attention because of its thermal stability and outstanding photovoltaic performance. However, further improvement of CsPbI3 device performance is hindered by significant energy losses via charge carrier recombination at the CsPbI3/transport layer interface and moisture sensitivity. Here, a beach chair shaped band structure is designed to introduce energy level gradients at both sides of the perovskite layer to steer optimal energy band alignment and heterojunction interface passivation in b CsPbI3 perovskite solar cells (PSCs) resulting in suppressed interfacial recombination, enhanced charge extraction, and more robust stability. As a result, champion solar cell efficiency is increased to as much as 17.12% one of the highest in reported CsPbI3 PSCs, and the Voc of 1.15 V is among the highest reported values. Furthermore, bare PSCs without encapsulation retain 90.4% of their initial cell efficiency after being stored for 1 month under ambient conditions.

title: Chemically Stable Black Phase CsPbI3 Inorganic Perovskites for High Efficiency Photovoltaics.
abstract: Research on chemically stable inorganic perovskites has achieved rapid progress in terms of high efficiency exceeding 19% and high thermal stabilities, making it one of the most promising candidates for thermodynamically stable and high efficiency perovskite solar cells. Among those inorganic perovskites, CsPbI3 with good chemical components stability possesses the suitable bandgap (1.7 eV) for single junction and tandem solar cells. Comparing to the anisotropic organic cations, the isotropic cesium cation without hydrogen bond and cation orientation renders CsPbI3 exhibit unique optoelectronic properties. However, the unideal tolerance factor of CsPbI3 induces the challenges of different crystal phase competition and room temperature phase stability. Herein, the latest important developments regarding understanding of the crystal structure and phase of CsPbI3 perovskite are presented. The development of various solution chemistry approaches for depositing high quality phase pure CsPbI3 perovskite is summarized. Furthermore, some important phase stabilization strategies for black phase CsPbI3 are discussed. The latest experimental and theoretical studies on the fundamental physical properties of photoactive phase CsPbI3 have deepened the understanding of inorganic perovskites. The future development and research directions toward achieving highly stable CsPbI3 materials will further advance inorganic perovskite for highly stable and efficient photovoltaics.

title: Intermediate phase assisted low temperature formation of g CsPbI3 films for high efficiency deep red light emitting devices
abstract: Black phase CsPbI3 is attractive for optoelectronic devices, while usually it has a high formation energy and requires an annealing temperature of above 300 degC. The formation energy can be significantly reduced by adding HI in the precursor. However, the resulting films are not suitable for light emitting applications due to the high trap densities and low photoluminescence quantum efficiencies, and the low temperature formation mechanism is not well understood yet. Here, we demonstrate a general approach for deposition of g CsPbI3 films at 100 degC with high photoluminescence quantum efficiencies by adding organic ammonium cations, and the resulting light emitting diode exhibits an external quantum efficiency of 10.4% with suppressed efficiency roll off. We reveal that the low temperature crystallization process is due to the formation of low dimensional intermediate states, and followed by interionic exchange. This work provides perspectives to tune phase transition pathway at low temperature for CsPbI3 device applications.

title: The postsynthetic anion exchange of CsPbI3 nanocrystals for photoluminescence tuning and enhanced quantum efficiency
abstract: CsPbI3 perovskite nanocrystals (NCs) are generally unstable, with low photoluminescence quantum yield (PLQY) and show deep red emission not suitable for optoelectronic applications. Herein, we propose a facile postsynthetic anion exchange method to enhance PLQY and stability via the controlled addition of ZnBr2 solution, in which the emission peak is adjusted from 690 nm to 550 nm and the PLQY was enhanced from about 50% to near unity (98% We further unveiled the ion exchange kinetics of the rapid transitions between two phases (CsPbI3 and CsPbBrI2) within 40 minutes, and also demonstrated that the electron trap and hole trap transformed mutually with the increase of halogen enabling the variable PLQYs. Moreover, the as prepared CsPbBrI2 NCs exhibit enhanced stability under UV irradiation and in water compared with that of pristine CsPbI3 NCs. The good stability and highly efficient narrow band emission centered at 630 nm for CsPbBrI2 NCs show its potential application possibility in liquid crystal display backlight. It is suggested that the postsynthetic ZnBr2 halogen ion exchange method demonstrated here opens a new door for the synthesis of high performance halide perovskite nanocrystals and the development of illumination and display applications.

title: Finding junction partners for CsPbI3 in a two terminal tandem solar cell: A theoretical prospect
abstract: Screening ideal partner materials for the CsPbI3 perovskite is crucial for developing all inorganic perovskite based tandem solar cells. Here, we quantize the performance of all inorganic tandem solar cells combining the CsPbI3 perovskite with c Si, GaAs, CdTe, CIGS, and CsSnI3, by analyzing the measured spectral efficiencies and developing macroscopic continuum device (MCD) model. Firstly, we integrate the MCD model and the principles of detailed balance (Shockley Queisser limit model, SQM) to investigate the top CsPbI3 solar cell with varying thickness and the rear sub cell with different bandgaps. Without considering the nonradiative recombination and absorptivity in the rear sub cell, an efficiency of over 32% can be reached by selecting the low bandgap materials (Egap 1.1 eV) as the rear sub cell. Furthermore, after the simulation by MCD model that takes the charge recombination, absorptivity and optimal thicknesses for both sub cells in tandem architectures into account, CIGS is found to be one of the best junction partners for CsPbI3. During the simulations, a unique bisection search algorithm is used to guarantee that the continuity of electric potential near the junction layer and the current matching of sub cells in the tandem solar cells. As a result, a CsPbI3(470 nm)/CIGS(2000 nm) tandem solar cell with the best modeled efficiency of 24.40% can be achieved, which is affirmed by a recent experimental result. Finally, we simulate the corresponding bifacial tandem photovoltaic device, and the optimal modeled efficiency can be further enhanced to 25.58%

title: Nanocrystallization of a CsPbI3 perovskite nanocrystals in GeS2 Sb2S3 based chalcogenide glass
abstract: Black a phase CsPbI3 of cubic perovskite structure receives intense attentions recently for its unique combination of high photoluminescence quantum yield, suitable bandgap, and long lifetime. However, a CsPbI3 presents poor chemical and thermodynamic stability under atmosphere condition. Here, we report a strategy for confining the a CsPbI3 perovskite into chalcogenide glassy matrix through controllable glass nanocrystallization. In the chalcogenide glass with an elaborately designed composition of 80GeS2*16Sb2S3*4CsPbI3, spherical a CsPbI3 nanocrystals were formed and observed clearly, which present good red photoluminescence centered at 701 nm. With the increasing heat treated temperature, the size of a CsPbI3 nanospheres increases, while the crystal quantity decreases. It is found that the nanocrystallization of a CsPbI3 nanospheres in chalcogenide glass is controlled by Ostwald ripening process.

title: High crystallinity and photovoltaic performance of CsPbI3 film enabled by secondary dimension
abstract: The photovoltaic performance of perovskite sloar cells (PSCs) is strongly dependent on the crystallinity, morphorlogy and defects of perovskite films. In the present work, a novel strategy was developed to fabricate the high quality CsPbI3 inorganic perovskite by tuning the growth dynamics of CsPbI3 by pretreatment of fresh CsPbI3 films with phenylethylamine iodide (PEAI) The PEAI can mediate the phase transformation from 1D (DMAPbI3) (DMA: dimethylammonium) to 3D CsPbI3 all inorganic perovskite films via the PEA2CsPb2I7 of 2D perovskite intermediate phase, resulting in highly crystalline CsPbI3 perovskite films with remarkably enlarged grains and reduced defects. The as achieved highly crystalline CsPbI3 inorganic perovskite not only exhibited improved phase stability but also significant reduced defects. The perovskite solar cells based on these CsPbI3 thin films exhibited a champion efficiency of 17.08% much higher than those prepared through posttreatment or direct addition of PEAI into CsPbI3 precursor solution. This work not only developed an effective strategy to prepare high crystalline CsPbI3 film and highly efficient CsPbI3 based all inorganic PSCs, but also unraveled the mediation mechanism of CsPbI3 by pre treatment of PEAI, shedding light for further development of high perfomance perovskite based optoelectronics.