Characterizing the Efficiency of Perovskite Solar Cells and Light-Emitting Diodes

Abstract

Metal halide perovskites (MHPs) are being widely studied as a lightabsorber for high-efficiency solar cells. With efforts being made throughout the globe, the power conversion efficiency of MHP solar cells has recently soared up to 25.2%. MHPs are now being spotlighted as a next-generation light-emitter as well. Their high color purity and solution-processability are of particular interest for display applications, which in general benefit from wide color gamut and low-cost high-resolution subpixel patterning. For this reason, research activities on perovskite light-emitting diodes (LEDs) are rapidly growing, and their external quantum efficiencies have been dramatically improved to over 20%. As more and more research groups with different backgrounds are working on these perovskite optoelectronic devices, the demand is growing for standard methods for accurate efficiency measurement that can be agreed upon across the disciplines and, at the same time, can be realized easily in the lab environment with due diligence. Herein, optoelectronic characterization methods are revisited from the viewpoint of MHP solar cells and LEDs. General efficiency measurement practices are first reviewed, common sources of errors are introduced, and guidelines for avoiding or minimizing those errors are then suggested to help researchers in fields develop the best measurement practice.

Dual‐Phase Regulation for High‐Efficiency Perovskite Light‐Emitting Diodes

“…In addition, many researchers have raised concerns about the data errors caused by different testing methods. [ 34,35 ] Thus, in addition to the EQE obtained by the luminance meter test system mentioned above, we used intergrading sphere method to measure the EQE of the Pero‐LEDs directly to double‐check the results. Figure S19 (Supporting Information) is the EQE histogram of the best 20 Pero‐LEDs devices, which presents an average EQE of 19.98%.…”

Operational and Spectral Stability of Perovskite Light-Emitting Diodes

“…As mentioned in the work of Choy et al, when the device was operated under a constant current density of 1.5 mA/cm 2 , the device exhibited an impressive lifetime of 3961 s, while in the case of 10 and 20 mA/cm 2 , the lifetime were 296 and 174 s, respectively. In order have more fair comparison on device operating stability, it is important to report performances with clear and detailed descriptions of test conditions (i.e., the value of constant voltage or current and the value of initial brightness or EQE) and develop test standards . Some works test the spectral stability for a short time, and whether the issue of spectral stability has been solved still needs to be verified under more stringent test conditions.…”

Polar or nonpolar? That is not the question for perovskite solar cells

“…Although further investigation is required to examine their validity, these methods have provided promising directions for future characterizations. In addition, macroscopic techniques, such as impedance spectroscopy [ 124 , 125 ], in combination with modeling and simulation, may provide valuable supporting data on the microscopic mechanisms. In this regard, integrating a local scanning probe with global macroscopic measurements in situ will provide invaluable microscopic insight into the macroscopic phenomena, which we are trying to develop, and it is particularly important to examine different and often competing dynamical processes from local relaxation studies [ 126 ].…”