A new, all room‐temperature solution process is developed to fabricate efficient, low‐cost, and stable perovskite solar cells (PVSCs). The PVSCs show high efficiency of 17.10% and 14.19%, with no ...hysteresis on rigid and flexible substrates, respectively, which are the best efficiencies reported to date for PVSCs fabricated by room‐temperature solution‐processed techniques. The flexible PVSCs show a remarkable power‐per‐weight of 23.26 W g−1.
The power conversion efficiency of organic–inorganic halide perovskite solar cells has exceeded 20% because of the outstanding properties of perovskite materials. However, the practical application ...of perovskite solar cells is hindered by their poor stability, which is related to the ion transport properties of perovskite materials. In this study, we explore an effective approach for reducing the migration of ions and improving the stability of solar cells by using mixed organic–inorganic perovskites. The structural and electronic properties of the mixed halide perovskites, namely, FMRCPbI and FMRCPbI, with various cation vacancies (VMA', VFA', VCs', and VRb') and the organic cation migration effects of MAPbI3, FAPbI3, and mixed FMRCPbI3 perovskites were investigated using first-principles method. FA cations exhibit high activation energy in the mixed FMRCPbI perovskite, suggesting that the diffusion of FA cations in FMRCPbI mixed perovskite is suppressed. In addition, radiation recombination is slightly small in FMRCPbI with a high concentration of cation vacancies due to the absence of energy levels of vacancy defects in the band gap. With its relatively low recombination loss and direct band gap with high absorption coefficient and high thermal stability, FMRCPbI mixed perovskite may be a new generation of highly efficient and emissive perovskites for photovoltaics and photoemission applications.
•Reducing the migration of ions and improving the stability of solar cells.•The organic cation migration effects of perovskites were investigated.•FA cations exhibit high activation energy in the mixed FMRCPbI perovskite.•The diffusion of FA cations in FMRCPbI mixed perovskite is suppressed.•FMRCPbI mixed perovskite may be a new generation perovskites for photovoltaics.
This review summarizes the optical and electrical models of bulk heterojunction (BHJ) polymer solar cells (PSCs) and numerically simulates and analyzes the performance of the PSCs. A complete ...simulation of a conventional BHJ device based on the polymer P3HT is presented and results are compared with the experimental data. Key factors affecting the device performance, including the photo absorption, quantum efficiency, short-circuit current fill factor, and open-circuit voltage of the device, are analyzed and summarized. Simulations on inverted, semitransparent and large-area PSCs are performed and findings are compared with experimental results. Simulations reveal the effects of optical spacer layers, different thicknesses, carrier mobilities, light intensities, contact barriers, effective bandgaps, recombination coefficients, and energy-level bending on the quantum efficiency, short-circuit current, fill factor, and open-circuit voltage of the PSCs. Differences between conventional and inverted geometry, opacity and semitransparency, and small and large-area PSCs are discussed based on the simulations. A power conversion efficiency of 11.0% is predicted for the PSC based on P3HT. Results suggest the need to further reduce the series resistance in large-area PSCs.
Perovskite light-emitting diodes (PeLEDs) prepared by the all-solution-process are gradually coming into view due to their low cost and flexible production process. However, the performance of ...CsPbBr3 device is limited by the high non-radiative recombination losses due to incomplete surface coverage and grain defects. Here a quaternary ammonium salt, tetrabutylammonium hexafluorophosphate (TBA-PF6) was simultaneously introduced into perovskite emission layers (CsPbBr3) and electron transport layer (TPBi (1,3,5-Tris(1-phenyl-1H-benzimidazol-2-yl) benzene) dissolved in ethyl acetate). As a result, the morphology and luminescence of CsPbBr3 films were improved, and the energy level of TPBi was more conducive to charge transport. Consequently, the maximum luminance and current efficiency of the modified green-emitting PeLEDs are improved. Furthermore, the optimized device had an operating life of more than 20 min at an initial luminance of 1230 cd/m2. This work provides a simple and easy method to be scaled up for the development of low-cost all-solution-processed PeLEDs.
Introduction of TBA-PF6 into CsPbBr3 and TPBi improves the brightness and operational stability of the perovskite light emitting diodes. Display omitted
•The introduction of TBA-PF6 into CsPbBr3 PeLED achieves to reduce the grain size and shrink the roughness of the films.•The energy levels of ETL are lowered after doping TBA-PF6 into TPBi, which is more favorable for charge transport.•The improvement of the stability of the optimized device is attributed to the enhanced resistance to water erosion.
Combining two-dimensional (2D) perovskites with other 2D materials to form a van der Waals (vdW) heterostructure has emerged as an intriguing way of designing electronic and optoelectronic devices. ...The structural, electronic, and optical properties of the 2D (PEA)2PbI4/black phosphorus (BP) PEA:(C4H9NH3)+ vdW heterostructure have been investigated using first-principles calculations. We found that the (PEA)2PbI4/BP heterostructure shows a high stability at room temperature. It is demonstrated that the (PEA)2PbI4/BP heterostructure exhibits a type-I band arrangement with high carrier mobility. Moreover, the band gap and band offset of (PEA)2PbI4/BP can be effectively modulated by an external electric field, and a transition from semiconductor to metal is observed. The band edges of (PEA)2PbI4 and BP in the (PEA)2PbI4/BP heterostructure, which show significant changes with the external electric field, provide further support. Furthermore, the BP layers can enhance the light absorption of the (PEA)2PbI4/BP heterostructures. Our results indicate that the 2D perovskite and BP vdW heterostructures are competitive candidates for the application of low-dimensional photovoltaic and optoelectronic devices.
Bifacial solar cells based on organic-inorganic perovskite are fabricated with a laminating process. The structure of the devices is ITO/SnO2/CH3NH3PbI3/NiOx/ITO, in which both electrodes are the ...transparent ITO layer. Therefore, the device can receive light from both sides. By laminating the two half-devices, ITO/SnO2/CH3NH3PbI3 and CH3NH3PbI3/NiOx/ITO, at high temperature with pressure, the merging of the middle perovskite layers is enhanced. The optimized bifacial PSCs show a Voc of 0.85 V, FF of 0.58, Jsc of 17.53 mA/cm2, and PCE of 8.47%. The photovoltaic performance varies when the light is illuminated from different sides of the bifacial PSCs. With illumination from the SnO2 side, the Voc and Jsc of the PSCs are apparently higher than those from the NiOx side, suggesting more severe electron-hole recombination at the NiOx/perovskite interface than at the SnO2/perovskite interface.
Amorphous undoped intrinsic silicon, B-doped silicon and P-doped silicon hybrid bilayer structures with poly(3-hexylthiophene) have been fabricated and their photovoltaic responses have been ...investigated. Open-circuit voltages and fill factors of the devices are moderate, but strongly dependent on the doping type of a-Si:H films. The highest available open-circuit voltage from the hybrid solar cells within this investigation is 1.23 V in a standard test condition. Both inorganic and organic semiconducting layers contribute to the photocurrent generation. The short-circuit currents appear to be limited by unbalanced charged carriers collected from different sides of the semiconductors, which indicates a way forward in device optimization.
•A series of hybrid structure of intrinsic or doped a-Si:H films with poly(3-hexylthiophene) (P3HT) were prepared.•P3HT was stable at rigorous RF PECVD deposition condition.•Devices with double-layer hybrid structures demonstrated photovoltaic responses.•The open-circuit voltage and fill factors are moderate, which are strongly dependent on the type of a-Si:H films.•The short-circuit current appears to be limited by the unbalanced charge-carrier mobility.
An interesting discotic triphenylene derivative, 2,7-biscarbethoxy-3,6,10,11-tetrapentyloxytriphenylene, can be homeotropically aligned on a large scale as a film on single substrates, i.e. the film ...with one side on the substrate and the other side freestanding. The alignment is achieved in a controlled condition close to a thermodynamic equilibrium state in a liquid crystal phase when interactions at the substrate surface are limited. Phase changing properties of this material are also a key factor in the alignment processes. The aligned structures are observed with an optical microscope. Within a single domain a hexagonal lattice of a d-spacing 16.3
Å is confirmed by X-ray diffraction measurement.
A new temperature measurement strategy based on the luminescence of Ce3+ and Tb3+ doped YBO3 was proposed. Dual emissions of Ce3+ and Tb3+ have different thermal dependencies, which can be used to ...overcome those limitations such as low signal discriminability and large measurement error. A series of Ce3+ and/or Tb3+ doped YBO3 samples were synthesized by hydrothermal method, and the influences of temperature on the photoluminescence (PL) intensity of Ce3+ 5d-4f transition and Tb3+ 4f-4f transition were discussed in detail. Compared with the single emission of YBO3:1.0%Ce3+, fluorescence intensity ratio (FIR) variation of Ce3+ blue emission and Tb3+ green emission in YBO3:1.0%Ce3+, 1.0%Tb3+ has been studied as a function of temperature in the range of 288–328 K. The absolute sensitivity of YBO3:1.0%Ce3+, 1.0%Tb3+ was 1.18 %K−1, higher than that of YBO3: 1.0%Ce3+ (0.70 %K−1). The results suggest that YBO3:Ce3+, Tb3+ is a good candidate as optical thermometry in the physiological range.
•Temperature dependence PL properties of YBO3:Ce3+ and YBO3:Ce3+, Tb3+ were evaluated in the range of 288–328 K.•The variation of fluorescence intensity ratio (FIR) of Ce3+/Tb3+ in YBO3 guarantees the absolute measurement of temperature.•The influence of Tb3+ dopant content on the sensitivity was investigated to optimize the capacity of temperature sensing.
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