Journal of Crystal Growth 587 (2022) 126637 Available online 21 March 2022 0022-0248/© 2022 Elsevier B.V. All rights reserved. Synthesis of (CH 3 NH 3 ) 2 CuCl 4 nanoparticles by antisolvent engineering M.T. Ahmed * , S. Islam , F. Ahmed Department of Physics, Jahangirnagar University, Dhaka 1342, Bangladesh A R T I C L E INFO Keywords: B1. Perovskites A1. Nanostructures A2. Antisolvent engineering B2. Superconducting materials ABSTRACT Improving the performance of devices while avoiding Pb toxicity is one of the most diffcult challenges in perovskite-based optoelectronic technology. Here, the solvent engineering method was employed to synthesize Cu-based organic–inorganic perovskite. The X-ray diffraction showed the monoclinic phase of the perovskites and different approximations verifed the nanocrystalline structure. Scanning electron microscopy shows grain size varying between 40 nm and 110 nm with an average grain size of 72 nm. The perovskite showed a fne absorption with a bandgap of 2.38 eV, suitable for visible light absorption. 1. Introduction Organic-inorganic perovskites (OIPs) are promising materials for a wide range of optoelectronic (OE) applications, including solar cells (SCs), lasers, light-emitting diodes (LEDs), optical detectors, and so on [1]. OIPs have been a popular choice among researchers in various areas due to improved device performance and a simple production method. In various studies, the most often employed OIPs are Pb-based perov- skites (MAPbX 3 , where MA = Methylammonium and X = halogen ion). Although the Pb-based OIPs demonstrated much-improved device per- formance, they are unstable and Pb-toxic. These drawbacks drive re- searchers to produce Pb-free perovskite materials with high better performance. Group-14 metals are the practicable atoms to substitute Pb and reduce toxicity in OIPs [2,3]. The rapid oxidation of Sn 2+ to Sn 4+ , on the other hand, results in poor cell performance [4]. As a result, one of the key aims is to replace toxic Pb in perovskites with more cost- effective, environmentally acceptable, less hazardous, and earth- abundant metals such as transition metals. As a transition metal, Cu is a well-established candidate for OIPs. The formula for Cu-based OIPs is (R-NH 3 ) 2 CuX 4 , where R is an organic cation and X is a halogen. The organic and metal halide layers are joined via hydrogen bonding, which is essential for structural stability [5]. Cui et al. (2015) successfully fabricated solar cells with superior visible wavelength absorption based on Cupric bromide OIPs [6]. However, they obtained a maximum power conversion effciency (PCE) of only 0.63%. In 2016, Cortecchia et al. employed the MA 2 CuCl x Br 4-x 2D crystalline structure as a light-absorbing layer in SCs [7]. They prepared a solution containing CuCl 2 , MABr, MACl, and CuBr 2 and changed the Br % to modify the energy bandgap between 2.48 eV (for MA 2 CuCl 4 ) and 1.80 eV (for MA 2 CuCl 0.5 Br 3.5 ). The prepared material proved to be rather stable despite having a much-reduced PCE. In 2018, Elseman et al. used a spin coating technique to synthesize MA 2 CuX 4 with different halides for SCs absorber layer [8]. MA2CuX4 bandgaps ranged from 2.36 eV to 1.04 eV for different halide mixtures. The PCE of MA 2 CuCl 4 was somewhat greater, at roughly 2.41%. However, Cu-based perovskite may be employed in a variety of OE applications because of the tunable bandgap feature. Evaporation of a precursor solution at low temperatures is the most common method of perovskite crystal production [9]. Though it is the most widely used method for producing perovskite crystals, it is time- consuming. Fast synthesis of perovskite crystals, on the other hand, is accomplished by combining an antisolvent with the precursor, allowing for rapid development of micro or nanocrystals in a short time [10]. Here we report the synthesis of MACC perovskite nanoparticles by antisolvent engineering. Further, the structural, optical, and electrical properties of anti-solvent engineered MACC were studied in this research. The crystallite size and band gap have been measured via different methods, which have not been previously done for MACC. 2. Experimental section 2.1. Materials CuCl 2 ⋅2H 2 O 99% (MERCK), methylamine (MA) solution 33 wt% (Sigma-Aldrich), diethyl ether (DE), hydrochloric acid (HCl) 32% (MERCK), and Dimethylformamide (DMF), Toluene. * Corresponding author. E-mail address: tanvir.phy43@gmail.com (M.T. Ahmed). Contents lists available at ScienceDirect Journal of Crystal Growth journal homepage: www.elsevier.com/locate/jcrysgro https://doi.org/10.1016/j.jcrysgro.2022.126637 Received 20 January 2022; Received in revised form 15 March 2022; Accepted 17 March 2022