Fang-Chung Chen

Organic solar cells (OSCs) have made remarkable progress over the past decade, driven by advancements in device architecture, interfacial engineering, and nonfullerene small‐molecule acceptors (NF–SMAs). The power conversion efficiency of OSCs has reached up to 21% due to the strong intramolecular charge‐transfer characteristics of NFSMAs and the work function aligning properties of self‐assembled monolayers (SAMs). Despite these achievements, OSCs still lag in terms of stability and scalability for commercialization. This review highlights the recent progress in SAM‐engineered OSCs, emphasizing their molecular designs, fabrication strategies, and multifunctional roles in work function modification, charge generation, transport, and extraction. Novel SAM design and functionalization approaches have also been addressed. Stability challenges, efficiency–durability tradeoffs, and scalability considerations are also discussed, offering insights into the future prospects of SAM‐integrated OSC technology. Further improvement through interfacial and morphology engineering is crucial for the large‐scale commercialization of OSCs.

Wide-bandgap (WBG) perovskite materials have attracted significant attention for applications in tandem solar cells and indoor photovoltaics owing to their favorable spectral-matching characteristics. Because different halide ions are often mixed to increase the bandgaps, WBG perovskites generally suffer from serious halide phase segregation, leading to high defect densities and short carrier lifetimes. These issues lead to enhanced nonradiative recombination and limited charge extraction, severely constraining the overall power conversion efficiency and operational stability of perovskite solar cells (PeSCs). In this work, we report on a new thin-film reconstruction method to improve the performance of WBG PeSCs with a 1.82eV bandgap. This method simultaneously combines surface defect passivators and cosolvents to reconstruct the surface of perovskite thin films. It effectively improves the crystallinity and energetic landscape of the perovskite films, thereby reducing defect density and optimizing charge transport. As a result, the PeSCs exhibit simultaneous enhancements in open-circuit voltages, short-circuit currents, and fill factors, as well as improved long-term operational stability. Specifically, the 1.82eV WBG PeSCs achieve a power conversion efficiency (PCE) of 17.03% under standard AM 1.5G illumination. Under a TL5 indoor light source, the devices deliver a PCE of 41.07%. This work demonstrates a simple yet effective surface reconstruction strategy that can substantially mitigate the efficiency and stability limitations of WBG perovskites under both solar and indoor illumination conditions.

High-speed, self-powered photodetectors (PDs) have been demonstrated using quadruple-cation lead-free antimony (Sb)-based perovskite-inspired materials (PIMs). The incorporation of phenylethylammonium iodide (PEAI) into the layered Sb-based PIM layers enhances film morphology and reduces defect density, thereby improving the device performance. As a result, the optimized PIM PDs exhibit a high responsivity of 210 mA W⁻¹, a detectivity on the order of 10¹² Jones, and an ultrafast −3 dB bandwidth of 542 kHz under zero bias, outperforming previously reported A₃B₂X₉-type PIM PDs. Although originally evaluated in a photovoltaic configuration, the devices also exhibit a power conversion efficiency of 1.72% and a high fill factor of 70%, underscoring the effectiveness of PEAI in regulating interfacial and bulk properties. This work highlights PEAI engineering as an effective strategy for advancing the photodetection performance of Sb-based PIM PDs and paves the way for high-speed, self-powered PDs for practical optoelectronic applications.

Two terminal-chlorinated ortho-benzodipyrrole (o-BDP)-based non-fullerene acceptors (NFAs), CFB-Cl and CMB-Cl, were designed and synthesized by incorporating fluorine or methyl substituents on the o-BDP core, respectively. Compared to their terminal-fluorinated counterparts, both NFAs exhibit red-shifted absorption, higher melting points, and stronger intermolecular interactions, attributed to the introduction of chlorinated end groups. Single-crystal X-ray analysis of CFB-Cl revealed a compact three-dimensional kaleidoscopic packing network stabilized by unique F···Cl halogen interactions between the fluorinated o-BDP core and the chlorinated end group, leading to a short π-π stacking distance of 3.38 Å and enhanced charge transport. Consequently, PM6:CFB-Cl devices achieved a PCE of 16.62% with a fill factor (FF) of 75.54%, outperforming PM6:CMB-Cl (PCE = 16.13%). To further improve device performance, a ternary blend strategy was employed by introducing the fluorinated CMB into PM6:CFB-Cl blends to extend the absorption range and improve the morphology. The resulting PM6:CFB-Cl:CMB inverted device exhibited excellent miscibility (χ = 0.02 K), balanced carrier transport (μ_e/μ_h = 1.38), suppressed recombination, and a highest PCE of 17.26% with J_sc = 26.02 mA cm^-2 and V_oc = 0.892 V. This work highlights the importance of halogen engineering in regulating molecular packing and charge dynamics, providing insights into the structure-morphology-performance relationship of o-BDP-based NFAs for next-generation organic photovoltaics.

A novel four-in-one (4-in-series) MicroLED-in-Package (MiP4) architecture is demonstrated for the first time, integrating four sub-85 µm blue micro-LED (µ-LED) dies on a transparent glass substrate through a redistribution-layer (RDL) interconnection process. The MiP4 device operates natively at 16 V, eliminating the need for step-down converters and simplifying high-voltage backlight driving circuits. The transparent glass carrier enables efficient light extraction, excellent thermal dissipation, and uniform emission. Electrical and optical characterization of dual- (B2), triple- (B3), and quad-chip (B4) devices shows ideal voltage scalability (8 V, 12 V, 16 V) and stable emission at 450 ± 2 nm with minimal FWHM broadening (22–29 nm). Compared with a commercial LED, the MiP4 delivers 1.8× higher optical power (~41.8 mW) despite its active area being only ~1/70 that of the reference device (20,000 µm² vs. 1,350,000 µm²), yielding a dramatically enhanced luminous flux density of 64 lm/mm² at 50 mA. Furthermore, pulse-driven measurements under 2%, 5%, and 10% duty cycles verify excellent thermal stability and minimal spectral shift (<1 nm), confirming the device’s robustness and energy efficiency. This first-of-its-kind 4-in-1 high-voltage glass-based µ-LED package provides a scalable and manufacturable route toward next-generation ultra-thin, high-brightness Mini-LED backlight and optical communication systems.

Organic‐thin film and perovskite solar cells are extremely promising because of their rapid progress in photovoltaic conversion efficiency (PCE). Beyond developing new materials and fabrication techniques, accurate performance characterization is essential for research and application. This study reports a round‐robin interlaboratory comparison of current density–voltage ( J–V ) characteristics under standard test conditions (STC) and external quantum efficiency (EQE) spectra for large‐area (>1 cm ² ) organic thin‐film, perovskite, as well as reference solar cells with distinct spectral responses. Among 20 participating laboratories, the relative deviation in PCE of the samples reaches an unprecedented 111%. A comprehensive analysis identifies critical obstacles to measurement accuracy, including total incident irradiance for the samples, EQE spectrum measurements for spectral mismatch factors (SMM), temperature control, and methodologies for obtaining the J–V curves. Based on these findings, corresponding recommendations are presented to enhance the accuracy of performance characterization for emerging solar cells.

Organic photodetectors (OPDs) have attracted significant attention due to their advantages over traditional inorganic semiconductor-based counterparts. Their features of low-cost processing, ease of bandgap tunability, flexible nature, and scalable processing make them great candidates for a wide range of photodetection platforms. Herein, we report photomultiplication-type OPDs prepared with non-fullerene acceptors (NFAs) exhibiting switchable operations between broadband and narrowband responses. The device can switch operations between narrowband and broadband detection modes based on the application of bias of different magnitudes. The use of NFAs extends the spectral response of the OPDs into the near-infrared spectral range. At the low bias of 0.3 V irrespective of polarity, the device shows narrowband responses with an external quantum efficiency (EQE) over 100 %. When the magnitude of bias exceeds 0.5 V, the device switches to broadband detection mode with a spectral range spanning from UV to NIR while maintaining the photomultiplication nature. To the best of our knowledge, high EQE values have never been reported in narrowband photodetectors with dual modes prepared with NFAs. Furthermore, the device shows a fast response up to 10 kHz, making it the fastest reported dual-mode NFA organic photodetector. Such dual-mode detection functionality is achieved without the need for an external optical filter and trans-impedance amplifier. This is beneficial for reducing the complexity of the device and thus greatly simplifies overall instrumentation needs for many applications.