A new generation of photothermal theranostic agents is developed based on PEGylated WS2 nanosheets. Bimodal in vivo CT/photoacoustic imaging reveals strong tumor contrast after either intratumoral or intravenous injection of WS2 -PEG. In vivo photothermal treatment is then conducted in a mouse tumor model, achieving excellent therapeutic efficacy with complete ablation of tumors. This work promises further exploration of transition-metal dichalcogenides for biomedical applications, such as cancer imaging and therapy.

A white light-emitting diode (0.33, 0.33) is fabricated using perovskite quantum dot/silica composites. It is shown to have greatly improved stability.

We report our experimental studies of surface-related emission in highly luminescent CdSe quantum dots (QDs) with controlled quantum yield and photooxidation by time-resolved photoluminescence measurements. This kind of surface-related emission, with a radiative lifetime of tens of nanoseconds, implies the involvement of surface states in the carrier recombination process of such highly luminescent CdSe QDs.

Bulk-heterojunction organic photovoltaic devices with nonfullerene acceptors (NFAs) exhibit efficient hole transfer with small interfacial energy offset, which results in power conversion efficiencies above 17% in single junction devices using the high-performance NFA of Y6. However, the underlying mechanism responsible for the hole transfer channel in the polymer/Y6 blends remains poorly understood. Herein, we report that the hole transfer channel of photocharge generation is mediated by an intra-moiety excited state in a blend of donor polymer PM6 and NFA Y6 using broadband transient absorption (TA) spectroscopy. By comparing the TA data recorded from the solution and film Y6 samples, we identify the ultrafast formation of an intra-moiety excimer state together with the conversion from the primary local excitation on a time scale of ∼0.2 ps in the Y6 film. The intra-moiety excimer state acts as the intermediate for the hole transfer channel, which dissociates into free polarons on a time scale of ∼15 ps in the PM6/Y6 blend at room temperature. The intra-moiety intermediate state, arising from the intermolecular coupling in Y6 domains, is markedly different from the interfacial charge transfer state, which is commonly accepted as the intermediate state for the electron transfer channel. These findings suggest that manipulating the interplay between intra-moiety and interfacial excited species can provide a promising route for further improving device performance.