Monolithic Dispersion Element‐Free Optical Spectrometer Fabricated by Combinatorial Inkjet‐Printing of Metal Halide Perovskites

ABSTRACT Metal halide perovskites (MHPs) have attracted considerable attention due to their exceptional performance as soluble and crystalline semiconductors. Although they are predominantly explored in the context of photovoltaics, their composition‐dependent bandgap also enables their application in light‐emitting diodes, photo‐, and x‐ray detectors. A key advantage of MHPs lies in their straightforward compositional tunability, achievable through combinatorial slot die coating or inkjet printing. This enables scalable and efficient fabrication of large‐area flexible electronic and optoelectronic devices. In this study, combinatorial inkjet printing was used to fabricate spectrally selective and compositionally matched photodetectors and optical filters, aiming to realize a fully printed monolithic optical spectrometer operating across the visible spectrum. The devices were produced using only three precursor inks to yield compositions of MAPb(I x Br 1‐x ) 3 and MAPb(Br x Cl 1‐x ) 3 , covering optical bandgaps between 1.6 and 3.1 eV. The resulting system represents a compact spectrometer without dispersive elements, achieving a spectral bandwidth as narrow as 30 nm.