Tailoring Crystal Structure of FA_0.83Cs_0.17PbI₃ Perovskite Through Guanidinium Doping for Enhanced Performance and Tunable Hysteresis of Planar Perovskite Solar Cells

Abstract

Current-voltage hysteresis of perovskite solar cells (PSCs) has raised the concern of accurate performance measurement in practice. Although various theories have been proposed to elucidate this phenomenon, the origin of hysteresis is still an open question. Herein, the use of guanidinium cation (Gu + )-dopant is demonstrated to tailor the crystal structure of mixed-cation formamidinium-cesium lead triiodide (FA 0.83 Cs 0.17 PbI 3 ) perovskite, resulting in an improved energy conversion efficiency and tunable current-voltage hysteresis characteristic in planar solar cells. Particularly, when the concentration of Gu-dopant for the perovskite film increases, the normal hysteresis initially observed in the pristine PSC is first suppressed with 2%-Gu-dopant, then changed to inverted hysteresis with a higher Gu-dopant. The hysteresis tunability behavior is attributed to the interplay of charge/ion accumulation and recombination at interfaces in the PSC. Furthermore, compared to the cell without Gu + -dopant, the optimal content of 2% Gu + -dopant also increases the device efficiency by 14%, reaching over 17% under one sun illumination.

Guanidinium Passivation for Air‐Stable Rubidium‐Incorporated Cs(1 − x)RbxPbI2Br Inorganic Perovskite Solar Cells

“…Apart from ion substitution, surface passivation is another commonly adopted method to fabricate efficient PSC with superior stability. There are a few reports that use different kinds of organic halide salts, such as guanidinium iodide (GAI), butylammonium iodide (BAI), phenethylammonium iodide (PEAI), octylammonium iodide (OAI), and dodecylammonium iodide (DAI), to passivate the perovskite surface. This can reduce trap density, restrain interface recombination, and increase the hydrophobicity of the perovskite films.…”

Crystallization Control of Ternary‐Cation Perovskite Absorber in Triple‐Mesoscopic Layer for Efficient Solar Cells

“…[24] Since there is a difference appearing between the reverse scan and the forward scan, it is difficult to confirm the real performance of devices. [35] The illumination stability of Cs x Rb y FA 1−x−y PbI 3 devices has been reported to own good illumination stability in maximum power point tracking (MPPT) test when perovskite is dealt with poly(methyl methacrylate) (PMMA) and stored in nitrogen. [34] In Figure 4c, the stabilized PCE is 16.26% and it is quite close to the PCE obtained at the reverse scan.…”

Strategically Constructed Bilayer Tin (IV) Oxide as Electron Transport Layer Boosts Performance and Reduces Hysteresis in Perovskite Solar Cells

“…Herein we demonstrate that the hysteresis for the B‐SnO 2 devices was not affected by increasing scan rate, which is in contrast to the S‐SnO 2 devices, which showed pronounced increase in hysteresis with increasing scan rate (Figure S5, Supporting Information), which could be attributed to the presence of a higher trap density . The general consensus in recent literature as to the observed photocurrent hysteresis phenomenon is multifactored in origin, a factor of both charge accumulation at a charge transport layer (inefficient extraction) and the presence of mobile ions . We assume the presence of mobile ions in our devices, given they appear to be ubiquitous to polycrystalline perovskite thin films even in devices with no observable hysteresis.…”