Charge transfer between acenes and PbS nanocrystals

Directional Defect Management in Perovskites by In Situ Decom-position of Organic Metal Chalcogenides for Efficient Solar Cells

Directional defects management in polycrystalline perovskite film with inorganic passivator is highly demanded while yet realized for fabricating efficient and stable perovskite solar cells (PSCs). Here, we develop a directional passivation strategy employing a two-dimensional (2D) material, Cu-(4-mercaptophenol) (Cu-HBT), as a passivator precursor. Cu-HBT combines the merits of the targeted modification from organic passivator and excellent stability offered by inorganic passivator. Featuring with dense organic functional motifs on its surfaces, Cu-HBT has the capability to "find" and fasten to the Pb defect sites in perovskites through coordination interactions during a spin-coating process. During subsequent annealing treatment, the organic functional motifs cleave from Cu-HBT and convert in situ into p-type semiconductors, Cu2 S and PbS. The resultant Cu2 S and PbS not only serve as stable inorganic passivators on the perovskite surface, significantly enhancing cell stability, but also facilitate efficient charge extraction and transport, resulting in an impressive efficiency of up to 23.5 %. This work contributes a new defect management strategy by directionally yielding the stable inorganic passivators for highly efficient and stable PSCs.

Probing surface states in PbS nanocrystal films using pentacene field effect transistors: controlling carrier concentration and charge transport in pentacene

We used a bilayer field effect transistor (FET) consisting of a thin PbS nanocrystals (NCs) film interfaced with vacuum-deposited pentacene to probe trap states in NCs.

Singlet exciton fission-sensitized infrared quantum dot solar cells

We demonstrate an organic/inorganic hybrid photovoltaic device architecture that uses singlet exciton fission to permit the collection of two electrons per absorbed high-energy photon while simultaneously harvesting low-energy photons. In this solar cell, infrared photons are absorbed using lead sulfide (PbS) nanocrystals. Visible photons are absorbed in pentacene to create singlet excitons, which undergo rapid exciton fission to produce pairs of triplets. Crucially, we identify that these triplet excitons can be ionized at an organic/inorganic heterointerface. We report internal quantum efficiencies exceeding 50% and power conversion efficiencies approaching 1%. These findings suggest an alternative route to circumvent the Shockley-Queisser limit on the power conversion efficiency of single-junction solar cells.