Novel modification of the TiO₂/CH₃NH₃PbI₃interface using glycine as a coupling agent induced higher coverage of perovskite through a two-step solution process.

Crystallinity and crystal orientation have a predominant impact on a materials’ semiconducting properties, thus it is essential to manipulate the microstructure arrangements for desired semiconducting device performance. Here, ultra‐uniform hole‐transporting material (HTM) by self‐assembling COOH‐functionalized P3HT (P3HT‐COOH) is fabricated, on which near single crystal quality perovskite thin film can be grown. In particular, the self‐assembly approach facilitates the P3HT‐COOH molecules to form an ordered and homogeneous monolayer on top of the indium tin oxide (ITO) electrode facilitate the perovskite crystalline film growth with high quality and preferred orientations. After detailed spectroscopy and device characterizations, it is found that the carboxylic acid anchoring groups can down‐shift the work function and passivate the ITO surface, retarding the interface carrier recombination. As a result, the device made with the self‐assembled HTM show high open‐circuit voltage over 1.10 V and extend the lifetime over 4,300 h when storing at 30% relative humidity. Moreover, the cell works efficiently under much reduced light power, making it useful as power source under dim‐light conditions. The demonstration suggests a new facile way of fabricating monolayer HTM for high efficiency perovskite devices, as well as the interconnecting layer needed for tandem cell.

This work demonstrates that the bis-adduct of [6,6]-phenyl-C₆₁-butyric acid methyl ester (PCBM) is an effective inhibitor of the aggregation of PCBM inside the poly(3-hexylthiophene) (P3HT) matrix. Substituting some of the PCBM with bis-PCBM apparently reduces the size of PCBM-rich clusters, enhancing both the short-circuit current density (J_SC) and the fill factor (FF), leading to a ∼17% increment in power conversion efficiency (PCE) for a cell with 8.3 wt% bis-PCBM replacement. More importantly, a tiny amount of bis-PCBM significantly improves the morphological stability of P3HT–PCBM blend against high-temperature aging. All P3HT–PCBM:bis-PCBM devices exhibit extremely stable PCEs, which do not visibly change upon heating at 150 °C for 15 hours.

The exMMTs, formed as a shell on top of CH ₃ NH ₃ PbI ₃ perovskite crystals, achieve ultra-stable unencapsulated PSCs.