2021 Adv. Funct. Mater., Phase Segregation Suppression of Wide-E_g Mixed-Halide PSC. Unlocking Dilemma of Voltage Deficit?

　　For applications in photovoltaics, wide bandgap (E_g) mixed-halide perovskites have attracted extensive attention. However, devices of wide bandgap (E_g) mixed-halide perovskites tend to have large voltage deficits due to the occurrence of phase separation, limiting the possibility of achieving high performance for the devices. Advanced Functional Materials (IF 18.808) published a study in December 2021 on increasing the voltage of mixed halide perovskites by suppressing phase separation. Through experiments and simulations, the research team explored the correlation between phase separation and voltage loss in wide bandgap (E_g) mixed halide perovskites.

　　The researchers used Enlitech’s SS-F5-3A solar simulator (now SS-X solar simulator) to perform current density-voltage (J-V) measurement, forward scan and reverse scan for unpackaged devices. The external quantum efficiency (EQE) detection was performed with the QE-R quantum efficiency measurement system of Enlitech. Taking the 1.67 eV wide bandgap (E_g) mixed-halide perovskite as an example, experiments confirmed the poor physical and electrical response of the control device. Through phase separation electrical simulations, the energy level mismatch of different wide bandgaps (E_g) results in extensive recombination, possibly resulting in performance degradation. The results of this research unlock the potential of halide perovskites to achieve high performance. In addition, the research team also proposed a depth-guided theory to illustrate strategies for improving the V_oc of wide bandgap (E_g) perovskites.

　　In addition to the EQE (External Quantum Efficiency) spectrum analysis of solar cells, the Quantum Efficiency Measurement System of Enlitech also provides J_sc (short-circuit current density) comparison for the short-circuit current of solar cells under the solar simulator to prove the authenticity of the experiment. Enlitech’s solar simulator and KA6000 software also provide monitoring of the short-circuit current over time to prove the stability of the solar cell!