“…Recently, low-dimensional metal halides have generated significant research interest in many optoelectronic applications due to their desirable photophysical properties. Among these, copper metal halides have emerged as a vital group due to their nontoxic nature and excellent optoelectronic properties, including simple synthesis and processing methods. − Cu(I)-based metal halides have been investigated in photodetectors, X-ray scintillators, image sensors, temperature sensors, memristors and neuromorphic computing, fluorescent inks, anticounterfeiting, and encryption applications. , Cu exhibits multiple coordination numbers, which can form 2D layers, 1D chains, and isolated 0D units . Additionally, the Cu(I) metal halides have a wide range of structural tunability; depending on the composition of ACuX (A: Cs, Rb, K, and X: Cl, Br, I), they form different crystal phases. − Each structure exhibits distinctive physical, chemical, and electronic properties.…”