Promote Carrier Transport Research Articles

Amine treatment induced perovskite nanowire network in perovskite solar cells: efficient surface passivation and carrier transport

In the fabrication of high efficiency organic–inorganic metal halide perovskite solar cells (PSCs), an additional interface modifier is usually applied for enhancing the interface passivation and carrier transport. In this paper, we develop an innovative method with in-situ growth of one-dimensional perovskite nanowire (1D PNW) network triggered by Lewis amine over the perovskite films. To our knowledge, this is the first time to fabricate PSCs with shape-controlled perovskite surface morphology, which improved power conversion efficiency (PCE) from 14.32% to 16.66% with negligible hysteresis. The amine molecule can passivate the trap states on the polycrystalline perovskite surface to reduce trap-state density. Meanwhile, as a fast channel, the 1D PNWs would promote carrier transport from the bulk perovskite film to the electron transport layer. The PSCs with 1D PNW modification not only exhibit excellent photovoltaic performances, but also show good stability with only 4% PCE loss within 30 days in the ambient air without encapsulation. Our results strongly suggest that in-situ grown 1D PNW network provides a feasible and effective strategy for nanostructured optoelectronic devices such as PSCs to achieve superior performances.

Plasmon-enhanced ZnO nanorod/Au NPs/Cu2O structure solar cells: Effects and limitations

Cu-based compounds can be a good candidate for a low cost solar cell material. In particular, Cu x O (x : 1–2) has a good visible light absorbing bandgap at 1–2 eV. As for using nanostructures in solar cell applications, metal nanoparticle-induced localized plasmon resonance is a promising way to increase light absorbance, which can help improve the efficiency of solar cells. We fabricated ZnO nanorod/Au nanoparticles/Cu2O nanostructures to study their solar cell performance. ZnO nanorods and Cu2O layer were synthesized by the electrodeposition method. Size-controlled Au nanoparticles were deposited using E-beam evaporator for localized surface plasmon resonance (LSPR) effect. By inserting Au plasmon nanoparticles and annealing Au NPs in solar cells, we could tune the maximum incident photon-to-current efficiency wavelength. However, the potential well formed by Au NP at the ZnO/Cu2O junction leads to charge-trapping, based on the constructed electronic band analysis. LSPR-induced hot carrier generation is proposed to promote carrier transport further in the presence of Au NPs.

Anisotropic Charge-Carrier Transport in High-Mobility Donor-Acceptor Conjugated Polymer Semiconductor Films.

Many high-performance solution-processable polymer thin-film transistors (PTFTs) have been reported. This contribution presents a comparative study of oriented films that have been deposited by means of solution shearing (SS) with charge-carrier transport anisotropy for PTFTs based on a diketopyrrolopyrrole-thiazolothiazole donor-acceptor copolymer (PDPPTzBT). The maximum field-effect mobility of the SS film of PDPPTzBT was 10.00 cm2 V-1 s. We also blended a solution of PDPPTzBT with a solution of polystyrene (PS). Solvent vapor annealing (SVA) lateral phase separation was adopted to block carrier transport in the direction of π-π stacking, and further evidence of charge transport anisotropy was provided. Highly oriented polymer films will further influence the carrier transport anisotropy and promote carrier transport along the backbone, and the performance of the field-effect transistor is thus improved.

Field‐Effect Transistors: Heterogeneous Nucleation Promotes Carrier Transport in Solution‐Processed Organic Field‐Effect Transistors (Adv. Funct. Mater. 3/2013)

In printed electronics, the drying semiconductor solution undergoes a solution-to-solid phase transformation that must yield optimal microstructure and performance. In small-molecule organic fieldeffect transistors (OFETs), it is crucial to yield films with large area lamellar coverage with excellent inplane p-stacking. On page 291 Aram Amassian and co-workers present new methodology and insight, which help to ensure that the drying solution crystallizes in optimal ways to promote carrier transport in OFETs.

A multilayered approach of Si/SiO to promote carrier transport in electroluminescence of Si nanocrystals

The electroluminescence (EL) and photoluminescence of Si nanocrystals (Si-nc) from multilayered samples of Si/SiO are investigated. Si-nc are formed within Si and SiO layers after furnace annealing. It is found that the presence of Si interlayers creates extra carrier paths for EL emission. A comparative study is further performed on a multilayered Si/SiO sample and a single-layered one with Si and SiO homogeneously mixed. Both samples have the same ratio of Si to O and the same contents of Si and O. The multilayered sample is found to have higher EL intensity, less turn-on voltage, lower resistance, and higher current efficiency than the single-layered one. The results indicate that Si interlayers in Si/SiO may act as carrier channels, which promote carrier transport and enhance the EL emission of Si-nc.