Ambient-Stable Cubic-Phase Hybrid Perovskite Reaching the Shockley–Queisser Fill Factor Limit via Inorganic Additive-Assisted Process

Abstract

Additive-assisted organic−inorganic perovskite materials have attracted substantial attention as photovoltaic light absorbers which lead to outstanding power conversion efficiency. Here we report an easy and effective fabrication of cubic-phase perovskite with an inorganic molecule additive like hydrazinium chloride (N 2 H 5 Cl, to be denoted as HZCl). We predict that this inorganic cation of N 2 H 5 + , which can substitute for the organic A-site in the perovskite structure, can tune Froḧlich polaron properties by controlling the interaction strength and the number of proton coordinations to halide. This prediction is experimentally demonstrated with an optimized perovskite device with 2% N 2 H 5 Cl additive, which exhibits an unprecedented 85% fill factor (FF) with the highest value close to the Shockley−Queisser limit. An extra power conversion efficiency (PCE) of 2.3% and a fill factor (FF) efficiency of 14% are boosted. These optimized performances by additive effects lead to a new approach based on the theoretical calculation toward an improved performance of the perovskite solar cell.

Machine Learning for Predicting the Band Gaps of ABX3 Perovskites from Elemental Properties

“…Light absorption coefficient is usually high in perovskites; so a device that has a thickness of only a few nanometers can be made to absorb the same amount of light as a micro-meter thick layer of silicon. Among other advantages of perovskites are the small exciton binding energies and the possibility to tune their band gap and electrical properties to a wide range of values by changing their composition and structure. ,− …”

Efficient, stable solar cells by using inherent bandgap of α-phase formamidinium lead iodide

“…Second, cation mixing in the FA sites affords entropic stabilization through the resulting entropic gain and small internal energy input to form their solid solution (32). Third, the stabilization of a-FAPbI 3 with MA cations can be explained by the presence of strong H bonds between the Iand H-N groups (33)(34)(35). The a-FAPbI 3 phase can be more easily stabilized when MA, Cs, or both is used with Brof small ionic radii, and highefficiency PSCs are normally fabricated using a-FAPbI 3 stabilized by mixed cations and anions.…”

Perovskite Passivation Strategies for Efficient and Stable Solar Cells

“…[128] Thus, a smaller amounts of MDA than MA can already structurally stabilize the α-FAPbI 3 . [129] As shown in Figure 8c, the UV-vis absorption and PL emission of FAPbI 3 :…”

“…[ 128 ] Thus, a smaller amounts of MDA than MA can already structurally stabilize the α‐FAPbI 3 . [ 129 ] As shown in Figure 8c, the UV–vis absorption and PL emission of FAPbI 3 : x MDACl 2 ( x = 0, 1.9, 3.8, and 5.7 mol%) slightly blue‐shifted with an increasing amount of MDACl 2 . The bandgap of FAPbI 3 perovskite slightly changed with the MDACl 2 .…”