Enhanced structural and optical performance of the novel 3-[(5-amino-1-phenyl-1H-pyrazol-4-yl)carbonyl]-1-ethyl-4-hydroxyquinolin-2(1H)-one heterojunction: experimental and DFT modeling

This study successfully and cost-effectively synthesized a novel compound, 3-[(5-amino-1-phenyl-1 H -pyrazol-4-yl)carbonyl]-1-ethyl-4-hydroxyquinolin-2(1 H )-one ( APPQ , 4 ), which displayed significant potential for various applications and yielded promising outcomes. Theoretical electronic absorption spectra in different media were acquired using the Coulomb-attenuating approach (CAM-B3LYP) and the Corrected Linear Response Polarizable Continuum Model (CLR) PCM. Employing CAM-B3LYP with the 6-311 + + G(d,p) level of DFT proved to be more accurate than alternative quantum chemical calculation methods, aligning well with the experimental data. Additionally, the CAM-B3LYP method using polarized split-valence 6-311 + + G(d,p) basis sets and CLR PCM in various solvents exhibited good agreement with the observed spectra. The high stability of APPQ , validated by the computed total energy and thermodynamic parameters at the same calculation level, surpassed that of anticipated structure 3 . The theoretically calculated chemical shift values ( 1 H and 13 C) and vibrational wavenumbers were strongly correlated with the experimental data. The APPQ thin films demonstrated a band gap energy of 2.3 eV through distinctive absorption edge measurement. Photoluminescence spectra exhibited characteristic emission peaks at approximately 580 nm. Current–voltage measurements on n-Si heterojunction devices with APPQ thin films revealed typical diode behavior. These APPQ -based devices showed attractive photovoltaic properties, including an open-circuit voltage of 0.62 V, a short-circuit current of 5.1 × 10 –4 A/cm 2 , and a maximum output power of 0.247 mW/cm 2 . Overall, the investigated heterojunctions display appealing photophysical characteristics, encouraging advancements in photovoltaics.