In this work, microwave synthesis, chemical, optical and electrochemical characterization of three small organic molecules, TPA-TPD, TPA-PT-TPD and TPA-TT-TPD with donor-acceptor structure and their use in organic photovoltaic cells are reported. For the synthesis, 5-(2-ethylhexyl)-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione was used as electron withdrawing fragment while the triphenylamine was used as electron donating fragment. Molecular electronic geometry and electronic distribution density were established by density functional theory (DFT) calculations and confirmed by optical and chemical characterization. These molecules were employed as electron-donors in the active layer for manufacturing bulk heterojunction organic solar cells, where [6,6]-phenyl C71 butyric acid methyl ester (PC71BM) was used as electron-acceptor. As cathode, Field′s metal (FM), an eutectic alloy (Bi/In/Sn: 32.5%, 51%, and 16.5%, respectively) with a melting point above 62 °C, was easily deposited by drop casting under vacuum-free process and at air atmosphere. Prepared devices based on TPA-TPD:PC71BM (1:4 w/w ratio) presented a large V_OC = 0.97 V, with J_SC = 7.9 mA/cm², a FF = 0.34, then, a power conversion efficiency (PCE) of 2.6%.

Organic solar cells (OSCs) are emerging as a viable alternative, and complementary niche of applications, to the conventional silicon-based photovoltaics due to their unique attributes, including flexibility, lightweight, semitransparency, and ease of processing. Recent breakthroughs in non-fullerene acceptors and advanced polymer donors have led to power conversion efficiencies exceeding 20%, closing the gap with traditional technologies. These advancements are driven by innovations in material design and engineering, enhanced understanding of device morphology, and improvements in fabrication architectures, as well as state-of-the-art characterization techniques. Despite these achievements, significant challenges remain, such as improving long-term device stability under environmental stress, upscaling OSCs from lab-scale devices to large-area modules through printing technologies, and achieving cost-effective scalability for mass production. This review also highlights OSCs’ transformative potential in niche applications such as semi-transparent photovoltaic windows, flexible/wearable electronics, and agricultural systems, paving the way for alternative sustainable and multifunctional energy solutions.

Herein is reported the synthesis of three new borinates (2a–2c) derived from bidentate imine ligands (1a–1c), which were prepared from the corresponding cinnamaldehyde derivatives. All compounds were characterized by MS, IR and NMR spectroscopy. The nonlinear optical (NLO) characterization of these molecules having push–pull properties is included. Second order nonlinearities were evaluated at 1.907 μm by the electric-field-induced second harmonic (EFISH) technique through the β×μ product, showing a trend for a general increase of the NLO response after boron complexation. For borinate 2c, which has strong electron-donating and electron-withdrawing groups at opposite ends of the π-backbone, βμ = 1560 × 10⁻³⁰ D cm⁵ esu⁻¹ , showing a three-fold increase with respect to the ligand 1c (βμ = 542 × 10⁻³⁰ D cm⁵ esu⁻¹ ). Third-order nonlinearities, in solid films, were evaluated employing the third harmonic generation (THG) Maker Fringe technique showing χ⁽³⁾ susceptibilities of the order of χ⁽³⁾∼10⁻¹² esu at the infrared wavelength of 1.2 μm. Compounds with the highest χ⁽³⁾ values correspond to those having the largest βμ product: for 1cχ⁽³⁾ = 1.1 × 10⁻¹¹ esu and for 2cχ⁽³⁾ = 8.4 × 10⁻¹² esu.