Effect of Perovskite Thickness on Electroluminescence and Solar Cell Conversion Efficiency

A hybrid organic-inorganic perovskite in a diode structure can lead to multifunctional device phenomena exhibiting both a high power conversion efficiency (PCE) of a solar cell and strong electroluminescence (EL) efficiency. Nonradiative losses in such multifunctional devices lead to an open circuit voltage (V_oc) deficit, which is a limiting factor for pushing the efficiency toward the Shockley-Queisser limit. In this work, we analyze and quantify the radiative limit of V_oc in a perovskite solar cell as a function of its absorber thickness. We correlate PCE and EL efficiency at varying thicknesses to understand the limiting factors for a high V_oc. With a certain increase in perovskite thickness, PCE improves but EL efficiency is compromised and vice versa. Thus, correlating these two figures of merit of a solar cell guides the light management strategy together with minimizing nonradiative losses. The results demonstrate that maximizing absorption and emission processes remains paramount for optimizing devices.