Themed collection FOCUS: Recent Progress on Perovskite Solar Cells

Organic–metal complexes (OMCs) are endowed with new functions and properties due to the characteristics of valence changes of metal ions and the diversity of organic molecular structures.

Self-assembled monolayers (SAMs) are wonderful interfacial modification materials for adjusting the energy level and passivating the defects.

This review introduces the elementary properties of the GA-based perovskite and summarizes the development history of utilizing guanidinium materials in PSCs, along with proposing a perspective of future opportunities and challenges.

This review critically analyses the chemical design and functionality of phthalocyanines in perovskite solar cells, which are generally applied in the perovskite layer, as the hole transport layer, or as an interlayer.

Small molecule dopant-free HTL with the ability to self-assemble shows a dual performance that leads to very similar efficiencies in p–i–n and n–i–p perovskite solar cells.

This work provides a simple and effective method to improve the performance of perovskite solar cells by replacing DMSO with FAI. As a result, the crystallinity and morphology of the perovskite layer are improved, and a PCE of 20.79% resulted with higher long-term stability.

An underlayer engineering strategy was developed by introducing octadecanammonium iodide (ODAI) as a crystallization buffer molecule to release residual strain for efficient tin perovskite solar cells.

A mesoporous SnO₂-electron transport bilayer with a high surface-area-to-volume ratio is developed for application in inkjet-printed PSCs (IJP-PSCs). The use of SnO₂-bilayer has uplifted the efficiency of IJP-PSCs up to a maximum of 16.9%.

Interlayer engineering via alkaline hypophosphates is used to improve the charge transport performance and device stability by adjusting energy band alignment and interfacial passivation, resulting in efficient and air-stable perovskite solar cells.

Inorganic cesium lead halide perovskites have gained increasing attention to boost photovoltaic performance and device stability.

A novel hole transporting material (SC-2) has been designed and synthesized. The pre-oxidized TFSI⁻salt has been synthesized and used as a p-dopant to achieve 21.3% power conversion efficiency for LiTFSI-free perovskite solar cells.

NH₄Cl doped with PEDOT: PSS is pprepared with facile and efficient approach demonstrates a superior photovoltaic performance in inverted perovskite solar cells due to enhanced conductivity and light-harvesting ability.

The solution-processability of perovskite solar cells (PVSCs) reduces the production cost, but renders a multi-crystalline film with a large number of grain boundaries, which hinders the charge transport and induces defects.

Thenoyltrifluoroacetone (TTA) modifies the perovskite/spiro-OMeTAD interface to inhibit Li⁺ migration from the hole transport layer to the perovskite layer and improves the performance of perovskite solar cells.

Carbon-based CsPbI₃ perovskite solar cells (C-PSCs) have attracted much interest due to their high chemical stability.

Emerging lead halide perovskite quantum dots (QDs) have attracted great research interest relative to conventional metal chalcogenide-based QDs for applications like solar cells.

Multifunctional complex molecules (CHM and BHM) were used to passivate interfacial defects, reduce the interfacial energy barrier, induce the orderly growth of perovskite crystals, and improve the PCE of HTL-free C-PSCs.

Cathode interface layers (CILs) play an important role in inverted perovskite solar cells (PVSCs) to correct the mismatched energy levels, improve electron extraction, and passivate interfacial defects.

Thiourea resin can improve the connection performances and energy level matching of the buried SnO₂/perovskite interface and suppress lead leakage through strong interactions.

Interplay of organic cation rotation and inorganic lattice fluctuation maintains the high performance of hybrid organic–inorganic perovskites.

Partially substituting Pb²⁺ with an appropriate amount of Sn²⁺ simultaneously reduces the bandgap and improves the quality and morphology of a CsPbBr₃ perovskite film.