Metal mesh: a design that revolutionizes the transparent conducting electrode (TCE) industry and drives the development of flexible optoelectronic technology.

Solution-processed triple-cation perovskite solar cells (PSCs) rely on complex compositional engineering or delicate interfacial passivation to balance the trade-off between cell efficiency and long-term stability. Herein, the facile fabrication of highly efficient, stable, and hysteresis-free tin oxide (SnO 2 )based PSCs is demonstrated with a champion cell efficiency of 20.06% using a green, halogen-free antisolvent. The antisolvent, composed of ethyl acetate (EA) solvent and hexane (Hex) in different proportions, works exquisitely in regulating perovskite crystal growth and passivating grain boundaries, leading to the formation of a crack-free perovskite film with enlarged grain size. The high quality perovskite film inhibits carrier recombination and substantially improves the cell efficiency, without requiring an additional enhancer/passivation layer. Furthermore, these PSCs also demonstrate remarkable long-term stability, whereby unencapsulated cells exhibit a power conversion efficiency (PCE) retention of ≈71% after >1500 hours of storage under ambient condition. For encapsulated cells, an astounding PCE retention of >98% is recorded after >3000 hours of storage in air. Overall, this work realizes the fabrication of SnO 2 -based PSCs with a performance greater or comparable to the state-of-the-art PSCs produced with halogenated antisolvents. Evidently, EA-Hex antisolvent can be an extraordinary halogenfree alternative in maximizing the performance of PSCs.

Improving the ohmic contact and interfacial morphology between an electron transport layer (ETL) and perovskite film is the key to boost the efficiency of planar perovskite solar cells (PSCs). In the current work, an amorphous–crystalline heterophase tin oxide bilayer (Bi‐SnO2) ETL is prepared via a low‐temperature solution process. Compared with the amorphous SnO2 sol–gel film (SG‐SnO2) or the crystalline SnO2 nanoparticle (NP‐SnO2) counterparts, the heterophase Bi‐SnO2 ETL exhibits improved surface morphology, considerably fewer oxygen defects, and better energy band alignment with the perovskite without sacrificing the optical transmittance. The best PSC device (active area ≈ 0.09 cm2) based on a Bi‐SnO2 ETL is hysteresis‐less and achieves an outstanding power conversion efficiency of ≈20.39%, which is one of the highest efficiencies reported for SnO2‐triple cation perovskite system based on green antisolvent. More fascinatingly, large‐area PSCs (active areas of ≈3.55 cm2) based on the Bi‐SnO2 ETL also achieves an extraordinarily high efficiency of ≈14.93% with negligible hysteresis. The improved device performance of the Bi‐SnO2‐based PSC arises predominantly from the improved ohmic contact and suppressed bimolecular recombination at the ETL/perovskite interface. The tailored morphology and energy band structure of the Bi‐SnO2 has enabled the scalable fabrication of highly efficient, hysteresis‐less PSCs.

Anion passivation effect on metal-oxide nano-architecture offers a highly controllable platform for improving charge selectivity and extraction, with direct relevance to their implementation in hybrid solar cells. In current work, we demonstrated the incorporation of fluorine (F) as an anion dopant to address the defect-rich nature of ZnO nanorods (ZNR) and improve the feasibility of its role as electron acceptor. The detailed morphology evolution and defect engineering on ZNR were studied as a function of F-doping concentration (x). Specifically, the rod-shaped arrays of ZnO were transformed into taper-shaped arrays at high x. A hypsochromic shift was observed in optical energy band gap due to the Burstein-Moss effect. A substantial suppression on intrinsic defects in ZnO lattice directly epitomized the novel role of fluorine as an oxygen defect quencher. The results show that 10-FZNR/P3HT device exhibited two-fold higher power conversion efficiency than the pristine ZNR/P3HT device, primarily due to the reduced Schottky defects and charge transfer barrier. Essentially, the reported findings yielded insights on the functions of fluorine on (i) surface –OH passivation, (ii) oxygen vacancies (Vo) occupation and (iii) lattice oxygen substitution, thereby enhancing the photo-physical processes, carrier mobility and concentration of FZNR based device.

A large-scale (64 cm2), spray-coated nickel oxide (NiO) film as a hole-transport layer has successfully yielded >17% efficiency in planar triple-cation perovskite solar cells (PSCs).