lizhendong

Nonfullerene acceptor FDICTF (2,9-bis(2methylene-(3-(1,1-dicyanomethylene)indanone))-7,​12-​dihydro-​4,​4,​7,​7,​12,​12-​hexaoctyl-​4H-​cyclopenta[2″,​1″:5,​6;3″,​4″:5′,​6′]​diindeno[1,​2-​b:1′,​2′-​b′]dithiophene) modified by fusing the fluorene core in a precursor, yields 10.06% high power conversion efficiency, and demonstrates that the ladder and fused core backbone in A–D–A structure molecules is an effective design strategy for high-performance nonfullerene acceptors.

Fullerene-free organic solar cells show over 11% power conversion efficiency, processed by low toxic solvents. The applied donor and acceptor in the bulk heterojunction exhibit almost the same highest occupied molecular orbital level, yet exhibit very efficient charge creation.

A sequential-casting ternary method is developed to create stratified bulk heterojunction (BHJ) solar cells, in which the two BHJ layers are spin cast sequentially without the need of adopting a middle electrode and orthogonal solvents. This method is found to be particularly useful for polymers that form a mechanically alloyed morphology due to the high degree of miscibility in the blend.

Air-stable doping of the n–type fullerene layer in an n–i–p planar heterojunction perovskite device is capable of enhancing device efficiency and improving device stability. Employing a (HC(NH₂)₂)_0.83Cs_0.17Pb(I_0.6Br_0.4)₃ perovskite as the photoactive layer, glass–glass laminated devices are reported, which sustain 80% of their “post burn-in” efficiency over 3400 h under full sun illumination in ambient conditions.

A series of wide-bandgap (WBG) copolymers with different alkyl side chains are synthesized. Among them, copolymer PBT1-EH with moderatly bulky side chains on the acceptor unit shows the best photovoltaic performance with power conversion efficiency over 10%. The results suggest that the alkyl side-chain engineering is an effective strategy to further tuning the optoelectronic properties of WBG copolymers.

Device stability of planar perovskite solar cells is improved by virtue of multifunctional BQ additive. The morphology and crystal quality of the perovskite films are improved because BQ slows the rate of perovskite crystal formation. Electron transfer from perovskite to BQ reduces charge-recombination losses, and the oxidizing ability of BQ effectively suppresses the formation of metallic lead and improves device lifetime.

A formamidinium(FA)-based perovskite showns superior optoelectronic properties including better stability than methylammonium-based counterparts. Pure FA-perovskite-based light-emitting diodes (LEDs) with high efficiency are reported. Interestingly, the LED clearly shows a sub-bandgap emission at 1.7 V (bandgap 2.3 eV). This important discovery provides further insights of the charge transport mechanism in perovskite-based optoelectronic devices.

Solution-processed CsPbBr₃ quantum-dot light-emitting diodes with a 50-fold external quantum efficiency improvement (up to 6.27%) are achieved through balancing surface passivation and carrier injection via ligand density control (treating with hexane/ethyl acetate mixed solvent), which induces the coexistence of high levels of ink stability, photoluminescence quantum yields, thin-film uniformity, and carrier-injection efficiency.

This paper firstly reports the effect of deoxyribonucleic acid (DNA) molecules extracted from chickpea and wheat plants on the injection/recombination of photogenerated electrons and sensitizing ability of dye-sensitized solar cells (DSSCs). These high-yield DNA molecules are applied as both linker bridging unit as well as thin tunneling barrier (TTB) at titanium dioxide (TiO₂ )/dye interface, to build up high-efficient DSSCs. With its favorable energy levels, effective linker bridging role, and double helix structure, bifunctional DNA modifier shows an efficient electron injection, suppressed charge recombination, longer electron lifetime, and higher light harvesting efficiency, which leads to higher photovoltaic performance. In particular, a photoconversion efficiency (PCE) of 9.23% is achieved by the binary chickpea and wheat DNA-modified TiO₂ (CW@TiO₂) photoanode. Furthermore, time-resolved fluorescence spectroscopy measurements confirm a better electron transfer kinetics for DNA-modified TiO₂ photoanodes, implying a higher electron transfer rate (k_ET). This work highlights a great contribution for the photoanodes that are linked with DNA molecule, which act as both bridging unit and TTB to control the charge recombination and injection dynamics, and hence, boost the photovoltaic performance in the DSSCs.

Two types of deoxyribonucleic acid molecules, extracted from fresh leaves of chickpea and wheat plants, employ as thin tunneling barrier at TiO₂/dye interface to minimize the recombination rates as well as linker bridging units for the electrons to move toward the TiO₂, thereby enhancing V_oc and J_sc. This strategy might open up new opportunities for the widespread fabrication and application of dye-sensitized solar cells.

Organic/inorganic halide perovskite nanoplatelets are exfoliated from microcrystals of the same material through ligand-assisted liquid-phase tip sonification, as described by L. Polavarapu, A. S. Urban, and co-workers on page 9478. The nanoplatelets are hundreds of nanometers large but extremely thin, down to a single-crystal-unit monolayer. Due to the strong quantum confinement, the transition energy of the nanoplatelets is shifted into the visible, leading to brightly fluorescing nanoplatelets of various colors.