Tuning and Enhancing Nonlinear Optical Behavior in Hybrid Arylammonium Perrhenate Salts through Halogen Substitution

Abstract

In the realm of optical and quantum computing, second-harmonic generation (SHG) serves as a valuable nonlinear optical element for both optical signal processing and quantum information processing. Herein, we report a series of innovative nonlinear optical (NLO) materials, denoted as (4-F-BTAB)ReO 4 , (4-Cl-BTAB)ReO 4 , and (4-Br-BTAB)ReO 4 (BTAB = para-halobenzyltrimethylammoniun), which show illustrious high-contrast "off-on−off" SHG conversion over a broad temperature range. The precise halogen modification of cations not only achieves significant SHG signal intensity (1.08 × KDP−3.23 × KDP) but also elevates phase transition temperatures from 415.5 to 474.4 K. Notably, (4-Br-BTAB)ReO 4 demonstrates a heightened SHG-active state with an increase of nearly 60 K, along with a wide band gap of 3.646 eV and enhanced piezoresponse performance of 2.25 V. This study contributes to the diversification of switchable NLO materials.

Room-Temperature Phase Transition Material with Switchable Second-Order Nonlinear Optical Properties

“…As an indispensable branch of NLO materials, those that can achieve reversible switching between nonlinear optics activation and deactivation are prominently significant in intelligent photoelectric sensing, control, and communication. , A newly developed and promising solid-state nonlinear optical switching strategy relies on structural phase transitions, which alter the second harmonic generation (SHG) signal by rearranging the noncentrosymmetric part. Specifically, abrupt changes in NLO response occur when centrosymmetric structures (such as NLO inactive states, SHG off) transform to noncentrosymmetric structures (such as NLO active states, SHG on) and vice versa. − Recently, molecule-based materials serve as appropriate candidates for NLO switching materials, not only due to their aptitude for the occurrence of order–disorder phase transitions but also smart responses to certain or multiple external stimuli, such as light, heat, electric field, magnetic field, and pressure, holding great prospects in next-generation photoelectric switches, sensors, and modulators. − In particular, the development of metal-free molecular materials with high-performance NLO properties has attracted widespread attention. − Organic metal-free solid NLO materials can significantly expand the application scope of optical devices, whereas those possessing NLO switchability near room temperature are still relatively rare. Devices made of NLO switching materials based on room-temperature reversible phase transitions are close to the daily life of humanity, such as applications related to health monitoring, wearable devices, and smart home systems, which can respond to moderate temperature variation or season change.…”

Second-Order Nonlinear Switching and Photoluminescence Properties of Cd-Based Hybrid Perovskite with High-Temperature Phase Transition

“…This process is highly sensitive to the symmetry properties of the material, typically requiring noncentrosymmetric structures apart from those crystallizing in the D 4 (422), D 6 (622), and O (432) point groups. − The ability to modulate the NLO effect by adjusting the composition and structure of the material enables precise control over the optical signal, facilitating the on–off switching mechanism. A particularly effective strategy for developing NLO switching materials is leveraging solid-to-solid structural phase transitions between noncentrosymmetric and centrosymmetric phases, allowing for reversible control of the SHG signal. − …”