Deciphering the capacitance frequency technique for performance-limiting defect-state parameters in energy-harvesting perovskites.

With emerging thin-film PIN-based optoelectronics devices, a significant research thrust is focused on the passivation of trap states for performance enhancement. Among various methods, the capacitance frequency technique (CFT) is widely employed to quantify the trap-state parameters; however, the trapped charge-induced electrostatic effect on the same is not yet established for such devices. Herein, we present a theoretical methodology to incorporate such effects in the CF characteristics of well-established, but not limited to, carrier-selective perovskite-based PIN devices.

On the Uniqueness of Ideality Factor and Voltage Exponent of Perovskite-Based Solar Cells.

Perovskite-based solar cells have attracted much recent research interest with efficiency approaching 20%. While various combinations of material parameters and processing conditions are attempted for improved performance, there is still a lack of understanding in terms of the basic device physics and functional parameters that control the efficiency. Here we show that perovskite-based solar cells have two universal features: an ideality factor close to two and a space-charge-limited current regime.