Albeit the organic-inorganic hybrid perovskites (OIHP) are considered to be frontline candidates owing to their intriguing optoelectronic properties, the unstable surfaces prone to degradation significantly affects the device performances and...

To improve and modulate the optoelectronic properties of singlecrystal (SC) metal halide perovskites (MHPs), significant progress has been achieved. Polymer-assisted techniques are a great approach to control the growth rate of SCs effectively. However, the resultant optoelectrical properties induced by polymers are ambiguous and need to be taken into the consideration. In this study, we have synthesized methylammonium lead triiodide (MAPbI 3 ) SCs using polyethylene glycol (PEG) and polystyrene (PS) polymers where PEG contains oxygen functionalities and PS does not. We studied the electrical properties of these SCs under dark and illumination conditions. It was observed that PEG-assisted SCs showed few defects with lower photocurrent as compared to the PS-assisted ones because of defect-mediated conductivity. The results are further verified by transient current response, responsivity, and capacitance−frequency measurements. The present study sheds light on the polymer selection for the growth of MHP SCs and their optoelectronic properties.

Size-dependent perovskite nanocrystals (PNCs) have manifested tremendous improvement in nonlinear optical (NLO) studies owing to their remarkable optical and electrical properties.

Owing to the striking properties, perovskite materials have clutched the interest in the field of optoelectronics. The property of being band tunable via composition alteration makes the perovskites fit in many optoelectronic applications. However, the compositional instability of mixed‐halide perovskites (MHPs) under illumination or by charge‐carrier injection is intercepting the exploitation of mixed‐halide strategy which effectively tailors the perovskite's bandgap. Herein, the segregation of halide ions in lattice promotes the formation of individual halide‐rich domains that severely influence the electronic band structures of the MHPs. In this scenario, extensive research is heading to perceive the mechanisms that drive the halide segregation and abate the process accordingly. As the impact of ion segregation directly determines the performance of the devices, in‐depth understanding is a prerequisite. This perspective provides a compressive understanding of different aspects such as structural origin, influence of light intensity, temperature, and atmospheric conditions that root the segregation process. A rigorous analytical discussion on approaches to play with cations and anions compositions, dimensionality, and Lewis base treatment that are detrimental for the halide segregation process is presented. This perspective contains a critical view on the halide segregation process that paves the route for future research.

Single crystals (SCs) of metal halide perovskites (MHPs) are known to possess superior properties. However, the surface of the SCs possesses a higher defect density, which can deteriorate the optoelectronic properties of SCs. Herein, we have engineered the growth of methylammonium lead tribromide SCs using (R)-3-aminopiperidine dihydrochloride (API). The modified crystals also showed improved photoresponse validated by the increased photocurrent. The modified crystal showed a highest photoresistivity of 0.47 mA/W and a detectivity of 3.7 × 1011 Jones at an applied bias of 2 V. On the other hand, the control crystal showed a resistivity of 0.32 mA/W and a detectivity of 1.0 × 1011 Jones. This shows that the API additive improves the charge collection efficiency and reduces the recombination. The charge accumulation and ion migration were further studied using electrochemical impedance spectroscopy and capacitance–frequency measurement. Thus, this study presents systematic investigation of the electrical response of additive-modified crystals.