arXiv subjects

Divine Mbachu

Publications and source records attributed to Divine Mbachu.

3 recordsLinked to original sources

arXiv2026

Metal Halide Perovskites for Violet and Ultraviolet Light Emission

Emissive metal halide perovskites (MHPs) have emerged as excellent candidates for next-generation optoelectronics due to their sharp color purity, inexpensive processing, and bandgap tunability. However, the development of violet and ultraviolet light-emitting MHPs has lagged behind due to challenges related to material and device stability, charge carrier transport, tunability into the ultraviolet spectrum, toxicity, and scalability. Here, we review the progress of both violet and ultraviolet MHP nanomaterials and light-emitting diodes, including materials synthesis and device fabrication across various crystal structures and dimensions (e.g., bulk thin films, 2D thin films, nanoplatelets, colloidal nanocrystals, and more) as well as lead-free platforms (e.g., rare-earth metal halide perovskites). By highlighting several pathways to continue the development of violet and ultraviolet light-emitting MHPs while also proposing tactics to overcome their outstanding challenges, we demonstrate the potential of state-of-the-art violet and ultraviolet MHP materials and devices for important applications in public health, 3D printing, nanofabrication, and more.

cond-mat.mtrl-sci↗

arXiv2025

Lead-Free Europium Halide Perovskite Nanoplatelets

Metal halide perovskites possess desirable optical, material, and electrical properties which have had substantial impact on next-generation optoelectronics. However, given the toxicity of lead, alternative lead-free perovskite semiconductors are needed. By fully replacing lead with rare-earth elements, one can simultaneously address toxicity concerns and achieve comparable optoelectronic performance. Here, we demonstrate the synthesis of two-dimensional europium halide perovskite nanoplatelets governed by the formula $\mathrm{L_{2}EuX_{4}}$ where L is an organic ligand and X is a halide anion. The structure, morphology, and composition of the nanoplatelets are confirmed by XRD, AFM, and XPS. Deep blue-emitting $\mathrm{PEA_{2}EuBr_{4}}$ perovskite nanoplatelets are synthesized in both the solution- and solid-states with photoluminescence emission centered at 446 nm and CIE color coordinates of (0.1515, 0.0327) and (0.1515, 0.0342), respectively. Additionally, near-ultraviolet $\mathrm{PEA_{2}EuCl_{4}}$ perovskite nanoplatelets are synthesized in both the solution- and solid-states with photoluminescence emission centered at 400 nm and 401 nm, respectively. Overall, europium halide perovskite nanoplatelets offer a lead-free alternative for deep blue, violet, and near-ultraviolet light emission $\unicode{x2013}$ charting new pathways for optoelectronics in this energy regime.

cond-mat.mtrl-sci↗

arXiv2024

Performance Analysis of a Photovoltaic System with Thermoelectric Generator and Phase Change Material; An Experimental Approach

This study explores the integration of thermoelectric generators (TEGs) and phase change materials (PCMs) to enhance the efficiency of photovoltaic (PV) panels in high-temperature conditions. An AP-PM-20 Polycrystalline PV panel, SP-1848-27145 Bismuth Telluride TEG, and paraffin wax PCM in an aluminum container were used. Four configurations were tested: standalone PV, PV-PCM, PV-TEG-PCM, and PV-PCM-TEG, under identical conditions from 10:30 AM to 6:00 PM at 25-minute intervals. Data on PV and TEG voltage, current, and solar irradiance were collected and analyzed. The results show significant performance improvements: the PV-PCM configuration boosted power output by 68.04%, while PV-PCM-TEG and PV-TEG-PCM configurations improved efficiency by 43.06% and 37.51%, respectively. Efficiency gains relative to the standalone PV system were 33.33% for PV-PCM, 25.76% for PV-PCM-TEG, and 21.21% for PV-TEG-PCM, demonstrating the effectiveness of PCMs and TEGs in enhancing PV performance.

eess.SY↗