Ternary blend approaches are demonstrated as a universal means to improve overall performance of organic photovoltaics (OPVs) in both indoor and outdoor conditions. A comparative study on two donors:one acceptor (2D:1A) and one donor:two acceptors (1D:2A) ternary blends shows that both approaches are universally effective for indoor and outdoor operation; the 1D:2A devices incorporating a nonfullerene acceptor (NFA) benefit from less charge recombination and higher power conversion efficiencies (PCEs) for various irradiation conditions, while the performance of the 2D:1A blends depends on the emission spectrum of the incident light source. The synergistic merits of NFAs and ternary structure in the 1D:2A ternary OPVs secure better performance and generality regardless of the incident lighting. A combination of experimental and theoretical analyses unveils that NFAs optimize packing and arrangement of molecules to build efficient cascade ternary junctions in the 1D:2A blends, which can be important design guidelines for the third component in ternary OPVs. The optimized 1D:2A ternary OPV exhibits a new record PCE of 25.6% under a 200 lux light‐emitting diode (LED) and 26.4% under a 1000 lux LED, and superior durability under industrial relevant thermal stress, suggesting new opportunities in diverse practical applications challenging the currently dominant PV technologies.

We demonstrate the improved morphological stability and lifetime of ternary organic solar cells incorporating nonfullerene small molecules in polymer:fullerene blends.

Energy‐storing functional photovoltaics, which can simultaneously harvest and store solar energy, are proposed as promising next‐generation multifunction energy systems. For the extension of conventional organic photovoltaics (OPVs), electrochromic supercapacitors (ECSs) are monolithically integrated with semitransparent (ST) quaternary blend‐based OPVs (ST Q‐OPVs) to achieve compact, energy‐efficient storage with great aesthetic appeal. In particular, ST Q‐OPVs with low‐power‐consumption ECSs allow full operation, even under low‐intensity irradiance, including artificial indoor light circumstances, and thereby exhibit potential for all‐day operating energy suppliers. The prepared ST energy‐storing functional photovoltaics also serve as a backup power source for external electronic equipment (e.g., light‐emitting diodes, and sensor nodes for Internet of Things) by consuming charged power. In addition to features that include unrestricted operation under any circumstances, color tunability, feasibility of designs with various shapes, rapid charging/discharging, and real‐time indication of stored energy levels, ST energy‐storing functional photovoltaics could potentially be applied in electronic devices such as advanced smart windows or portable smart electronics.

The unique properties of organic photovoltaics (OPVs) offer great promise in emerging applications such as wearable electronics or the Internet of Things. For their successful utilization, OPV operation should be designed for versatile irradiation circumstances in addition to solar light since they should be capable of providing electric power when there is no sunlight or when they operate indoors. Here, a quaternary OPV (Q-OPV) as a semitransparent, colorful energy platform that operates efficiently under both solar and artificial light irradiation is demonstrated. The experimentally optimized Q-OPV shows a broadened spectral response and improved charge transport process with suppressed recombination, thereby providing high output powers that are sufficient to autonomously operate low-power electronic devices. In addition, the Q-OPV benefits from improved morphological stability with a reduced driving force for grain growth by the increased entropy in the quaternary blend system. The important features of the Q-OPV platform such as semitransparency, high tolerance to film thickness, and color codability, while pursuing the improved performance and thermal durability, further open new opportunities as an all-day (24/7/365) power generator in broad practical applications.

We report high-performance all-inkjet-printed organic thin-film transistors (OTFTs), where inkjet-printed silver electrodes, cross-linked poly(4vinylphenol) (PVP) and 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-pentacene) were used as gate/source/drain electrodes, a gate dielectric layer and an active semiconductor layer, respectively. To evaluate quality of the active semiconductor layer, we also fabricated OTFTs by using spin-coating and drop-casting methods for TIPS-pentacene layer on the inkjet-printed PVP gate dielectric layer. Comparable TFT electrical performances were obtained and well-crystallized TIPS-pentacene layer was formed for all cases. All TIPS-pentacene OTFTs show lower sub-threshold swing values than OTFTs with an evaporated pentacene active semiconductor layer on the inkjet-printed PVP gate dielectric layer. By using optimized inkjet-printing conditions, we obtained mobility of 0.06 cm 2 V À1 s À1 and on/off ratio of 10 4 for all-inkjet-printed OTFT.

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The effect of cadmium arachidate (CdA) layers deposited by Langmuir-Blodgett technique on the growth of pentacene thin films and the performance of pentacene-based thin film transistors has been investigated. The hydrophobicity of the SiO2 gate dielectric surface was increased (surface energy reduced) with the deposition of CdA layers as a result of the presence of long hydrophobic alkyl chains attached to the cadmium atoms. The change in surface wetting properties of SiO2 strongly influenced the growth mechanism of pentacene thin films. The grain size and root-mean-square surface roughness of pentacene was decreased with an increase in the number of CdA layers compared to the pentacene deposited on a bare SiO2 surface. Organic thin film transistors (OTFTs) with seven layers of CdA on SiO2 showed the highest mobility of 0.27 cm2/Vs and the lowest subthreshold slope of 2.4 V/dec. The enhanced electrical properties of the OTFTs with SiO2/CdA as the dielectric is attributed to the better intermolecular connection, tight packing, and improved surface quality of the pentacene, as evident from the X-ray diffraction (XRD) and atomic force microscopy (AFM) results.

Solution-based metal oxide semiconductors (MOSs) have emerged, with their potential for low-cost and low-temperature processability preserving their intrinsic properties of high optical transparency and high carrier mobility. In particular, MOS field-effect transistors (FETs) using the spray pyrolysis technique have drawn huge attention with the electrical performances compatible with those of vacuum-based FETs. However, further intensive investigations are still desirable, associated with the processing optimization and operational instabilities when compared to other methodologies for depositing thin-film semiconductors. Here, we demonstrate high-performing transparent ZnO FETs using the spray pyrolysis technique, exhibiting a field-effect mobility of ~14.7 cm2 V−1 s−1, an on/off ratio of ~109, and an SS of ~0.49 V/decade. We examine the optical and electrical characteristics of the prepared ZnO films formed by spray pyrolysis via various analysis techniques. The influence of spray process conditions was also studied for realizing high quality ZnO films. Furthermore, we measure and analyze time dependence of the threshold voltage (Vth) shifts and their recovery behaviors under prolonged positive and negative gate bias, which were expected to be attributed to defect creation and charge trapping at or near the interface between channel and insulator, respectively.