Enhanced Thermal Stability of InAs Colloidal Quantum Dot Films With AlBr 3 Ligands

III‐V group colloidal quantum dots (CQDs) are promising semiconductors for short‐wavelength infrared optoelectronic devices because of their narrow bandgaps and size tunability. Furthermore, their composition complies with the ‘Restriction of Hazardous Substances’ directive of the European Union, making them attractive for consumer electronics, including photodetectors and light‐emitting diodes. However, achieving surface passivation comparable to that of well‐studied Pb chalcogenides demonstrated to be challenging. Currently, the device performance of InAs CQDs with InBr 3 ‐based ligands obtained via solution‐phase ligand exchange is limited, indicating insufficient surface passivation. In this study, we introduce for InAs CQDs with excitonic peak centered at approximately 1200 nm, a novel AlBr 3 ‐ligand with methylammonium acetate (MAAc) as co‐ligand. The resulting CQDs show enhanced photoluminescence intensity indicating better surface passivation, attributed to the reduced steric hindrance of Al cations. The transport properties of the films obtained from inks yield a maximum field‐effect mobility of 0.26 cm 2 V − 1 s − 1 with ion gel gating. The CQD films obtained with the new inks also maintain stable optoelectronic properties at temperatures up to 200°C. This enhanced thermal stability represents a crucial step toward Pb‐free CQD‐based optoelectronics for consumer applications.