Although the efficiencies of all-perovskite tandem solar cells have surpassed 26%, further advancement of device performance is constrained by the large photovoltage deficit in wide-band-gap perovskite subcells. Meanwhile, state-of-the-art charge recombination layers incorporate an additional thin metal film (Au or Ag), which not only complexes device fabrication but induces parasitic optical losses. Here, we first fabricate efficient wide-band-gap perovskite solar cells (PSCs) with by suppressing nonradiative losses both in bulk material and at interface. The prepared PSCs with a band gap of 1.71 eV yield an impressive open-circuit voltage (V OC) of 1.27 V, giving a small V OC deficit of 0.44 V and an efficiency of 20.8%. We then fabricate monolithic all-printed perovskite tandem devices by constructing a metal-free recombination layer, which yields an efficiency of 23.65% and a high V OC of 2.05 V. This work offers a simple yet effective charge recombination architecture for advancing the performance of all-perovskite tandem devices.

SnO2 electron transport layer (ETL) plays a critical role in constructing a planar perovskite solar device. Improving SnO2 ETL properties and understanding of interfacial energy loss are key factors to fabricate highly efficient and reproducible perovskite solar cells (PSCs). Herein, a nonionic surfactant, polyethylene oxide‐polypropylene oxide‐polyethylene oxide (P123), is introduced to suppress the aggregation of SnO2 nanoparticles for a uniform SnO2 ETL. The P123 polymer can maintain the SnO2 colloidal size around 10 nm over 72 h at 35 °C and thus promote the dispersion of nanoparticles in SnO2 precursor. By spin coating P123‐doped SnO2 (SnO2‐P) colloid, the compactness and uniformity of SnO2 layer are improved significantly. Correspondingly, SnO2‐P‐based devices demonstrate a champion efficiency with enhanced open‐circuit voltage (V OC) of 1.162 V. Due to the SnO2/perovskite interface binding interaction, the devices gain a high long‐term stability, retaining 85% of their initial performance after 1000 h storage in air. Equally important, the polymer‐regulated ETL allows a competitive efficiency of 17.44% with active area of 1.00 cm2, exhibiting much potential for large‐scale solar devices. This ETL modification approach provides a new and simple route to improve the quality of SnO2 colloid solution for fabricating efficient perovskite devices.

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Effective electron transport layer (ETL) plays a pivotal role in suppressing nonradiative recombination at interface, as well as promoting perovskite crystallization to facilitate electron extraction in solar cells (PSCs). Herein,...

The low formation energies of metal halide perovskites endow them with potential luminescent materials for applications in information encryption and decryption. However, reversible encryption and decryption are greatly hindered by the difficulty in robustly integrating perovskite ingredients into carrier materials. Here, we report an effective strategy to realize information encryption and decryption by reversible synthesis of halide perovskites, on the lead oxide hydroxide nitrates (Pb 13 O 8 (OH) 6 (NO 3 ) 4 ) anchored zeolitic imidazolate framework composites. Benefiting from the superior stability of ZIF-8 in combination with the strong bond between Pb and N evidenced by X-ray absorption spectroscopy and X-ray photoelectron spectroscopy, the as-prepared Pb 13 O 8 (OH) 6 (NO 3 ) 4 −ZIF-8 nanocomposites (Pb−ZIF-8) can withstand common polar solvent attack. Taking advantage of blade-coating and laser etching, the Pb−ZIF-8 confidential films can be readily encrypted and subsequently decrypted through reaction with halide ammonium salt. Consequently, multiple cycles of encryption and decryption are realized by quenching and recovery of the luminescent MAPbBr 3 −ZIF-8 films with polar solvents vapor and MABr reaction, respectively. These results provide a viable approach to integrate the state-of-the-art materials perovskites and ZIF for applications in information encryption and decryption films with large scale (up to 6 × 6 cm 2 ), flexibility, and high resolution (approximate 5 μm line width).