Significant Efficiency Enhancements in Non-Y Series Acceptors by the Addition of Outer Side Chains.

Most current highly efficient organic solar cells utilize small molecules like Y6 and its derivatives as electron acceptors in the photoactive layer. In this work, a small molecule acceptor, SC8-IT4F, is developed through outer side chain engineering on the terminal thiophene of a conjugated 6,12-dihydro-dithienoindeno[2,3-d:2',3'-d']-s-indaceno[1,2-b:5,6-b']dithiophene (IDTT) central core. Compared to the reference molecule C8-IT4F, which lacks outer side chains, SC8-IT4F displays notable differences in molecule geometry (as shown by simulations), thermal behavior, single-crystal packing, and film morphology.

Ultrafast Coherent Hole Injection at the Interface between CuSCN and Polymer PM6 Using Femtosecond Mid-Infrared Spectroscopy.

Tracking the dynamics of ultrafast hole injection into copper thiocyanate (CuSCN) at the interface can be experimentally challenging. These challenges include restrictions in accessing the ultraviolet spectral range through transient electronic spectroscopy, where the absorption spectrum of CuSCN is located. Time-resolved vibrational spectroscopy solves this problem by tracking marker modes at specific frequencies and allowing direct access to dynamical information at the molecular level at donor-acceptor interfaces in real time.

High-Performance Near-Infrared Absorbing n-Type Porphyrin Acceptor for Organic Solar Cells.

While the outstanding charge transport and sunlight-harvesting properties of porphyrin molecules are highly attractive as active materials for organic photovoltaic (OPV) devices, the development of n-type porphyrin-based electron acceptors has been challenging. In this work, we developed a high-performance porphyrin-based electron acceptor for OPVs by substitution of four naphthalene diimide (NDI) units at the perimeter of a Zn-porphyrin (P) core using ethyne linkage. Effective π-conjugation between four NDI wings and the P core significantly broadened Q-band absorption to the near infrared region, thereby achieving the narrow band gap of 1.

Development of n-Type Porphyrin Acceptors for Panchromatic Light-Harvesting Fullerene-Free Organic Solar Cells.

The development of n-type porphyrin acceptors is challenging in organic solar cells. In this work, we synthesized a novel n-type porphyrin acceptor, P-TNI, via the introduction of the electron withdrawing naphthalene imide (NI) moiety at the meso position of zinc porphyrin (P). P-TNI has excellent thermal stability and unique bimodal absorption with a strong Soret band (300-600 nm) and weak Q-band (600-800 nm).

11% Organic Photovoltaic Devices Based on PTB7-Th: PCBM Photoactive Layers and Irradiation-Assisted ZnO Electron Transport Layers.

The enhancement of interfacial charge collection efficiency using buffer layers is a cost-effective way to improve the performance of organic photovoltaic devices (OPVs) because they are often universally applicable regardless of the active materials. However, the availability of high-performance buffer materials, which are solution-processable at low temperature, are limited and they often require burdensome additional surface modifications. Herein, high-performance ZnO based electron transporting layers (ETLs) for OPVs are developed with a novel -ray-assisted solution process.

Artificial light-harvesting n-type porphyrin for panchromatic organic photovoltaic devices.

A near-infrared-harvesting n-type porphyrin-based acceptor for organic photovoltaics (OPVs) was developed. The n-type acceptor, PDI-P-PDI, was designed by connecting a zinc porphyrin (P) core to two perylenediimide (PDI) wings through ethyne bridges. A narrow bandgap of 1.

Fullerene-Free Organic Solar Cells with an Efficiency of 10.2% and an Energy Loss of 0.59 eV Based on a Thieno[3,4-c]Pyrrole-4,6-dione-Containing Wide Band Gap Polymer Donor.

Although the combination of wide band gap polymer donors and narrow band gap small-molecule acceptors achieved state-of-the-art performance as bulk heterojunction (BHJ) active layers for organic solar cells, there have been only several of the wide band gap polymers that actually realized high-efficiency devices over >10%. Herein, we developed high-efficiency, low-energy-loss fullerene-free organic solar cells using a weakly crystalline wide band gap polymer donor, PBDTTPD-HT, and a nonfullerene small-molecule acceptor, ITIC. The excessive intermolecular stacking of ITIC is efficiently suppressed by the miscibility with PBDTTPD-HT, which led to a well-balanced nanomorphology in the PBDTTPD-HT/ITIC BHJ active films.

High-Efficiency Photovoltaic Devices using Trap-Controlled Quantum-Dot Ink prepared via Phase-Transfer Exchange.

Colloidal-quantum-dot (CQD) photovoltaic devices are promising candidates for low-cost power sources owing to their low-temperature solution processability and bandgap tunability. A power conversion efficiency (PCE) of >10% is achieved for these devices; however, there are several remaining obstacles to their commercialization, including their high energy loss due to surface trap states and the complexity of the multiple-step CQD-layer-deposition process. Herein, high-efficiency photovoltaic devices prepared with CQD-ink using a phase-transfer-exchange (PTE) method are reported.

Improved performance of dye-sensitized solar cells using dual-function TiO(2) nanowire photoelectrode.

A unique, hierarchically structured, aggregated TiO(2) nanowire (A-TiO(2)-nw) is prepared by solvothermal synthesis and used as a dual-functioning photoelectrode in dye-sensitized solar cells (DSSCs). The A-TiO(2)-nw shows improved light scattering compared to conventional TiO(2) nanoparticles (TiO(2)-np) and dramatically enhanced dye adsorption compared to conventional scattering particles (CSP). The A-TiO(2)-nw is used as a scattering layer for bilayer photoelectrodes (TiO(2)-np/A-TiO(2)-nw) in DSSCs to compare the cell performance to that of devices using state-of-the-art photoelectrode architectures (TiO(2)-np/CSP).