摘要： Owing to its suitable bandgap and remarkable thermal stability, all-inorganic perovskite CsPbI2Br has caught the eye of the academic research and industry recently. However, it still suffers from a phase transition due to poor stability at ambient atmosphere. Here, we introduce CsBr as an interfacial layer between the electron transport layer and the CsPbI2Br perovskite absorber layer to induce a more favorable perovskite crystal growth and fabricated devices with a facile structure of (ITO/SnO2/CsBr/CsPbI2Br/Spiro-OMeTAD/Ag). The CsBr buffer layer plays a role in reducing the lattice mismatch so that it cannot only induce and manage the formation of CsPbI2Br film but also significantly enhance the phase stability of the perovskite. After the modification, the devices reveal conspicuous improvement in illuminated, thermal, ambient, and long-term stabilities without any encapsulation. Meanwhile, the device performance is also improved. The unencapsulated CsBr treated device manifests illuminated stability with PCE remaining almost above 80 % of its initial value after long-time exposure, the remarkable thermal stability of remaining over 78 % of the initial values, better humid resistance, and only 13% decline after being stored in N2 glove-box over 40 days.