Nonlinear optical effects in layered two-dimensional transition metal chalcogenides have been extensively explored recently because of the promising prospect of the nonlinear optical effects for various optoelectronic applications. However, these materials possess sizable bandgaps ranging from visible to ultraviolet region, so the investigation of narrow-bandgap materials remains deficient. Here, we report our comprehensive study on the nonlinear optical processes in palladium diselenide (PdSe₂) that has a near-infrared bandgap. Interestingly, this material exhibits a unique thickness-dependent second harmonic generation feature, which is in contrast to other transition metal chalcogenides. Furthermore, the two-photon absorption coefficients of 1–3 layer PdSe₂ (β ~ 4.16 × 10⁵, 2.58 × 10⁵, and 1.51 × 10⁵ cm GW⁻¹) are larger by two and three orders of magnitude than that of the conventional two-dimensional materials, and giant modulation depths (α_s ~ 32%, 27%, and 24%) were obtained in 1–3 layer PdSe₂. Such unique nonlinear optical characteristics make PdSe₂ a potential candidate for technological innovations in nonlinear optoelectronic devices.

We constructed an intelligent cloud lab that integrates lab automation with cloud servers and artificial intelligence (AI) to detect chirality in perovskites. Driven by the materials acceleration operating system in cloud (MAOSIC) platform, on-demand experimental design by remote users was enabled in this cloud lab. By employing artificial intelligence of things (AIoT) technology, synthesis, characterization, and parameter optimization can be autonomously achieved. Through the remote collaboration of researchers, optically active inorganic perovskite nanocrystals (IPNCs) were first synthesized with temperature-dependent circular dichroism (CD) and inversion control. The inter-structure (structural patterns) and intra-structure (screw dislocations) dual-pattern-induced mechanisms detected by MAOSIC were comprehensively investigated, and offline theoretical analysis revealed the thermodynamic mechanism inside the materials. This self-driving cloud lab enables efficient and reliable collaborations across the world, reduces the setup costs of in-house facilities, combines offline theoretic analysis, and is practical for accelerating the speed of material discovery.

Deciphering singlet-to-triplet intersystem crossing (ISC) in organic near-infrared photosensitizers (PSs) is of fundamental importance in the designing of high-performance PSs to boost the clinical usage of photodynamic therapy (PDT). However, in-depth investigations of the ISC dynamics in near-infrared PSs have not been performed to date. Here, systematical investigations of the ISC dynamics in organic near-infrared BODIPY derivatives are presented, in which a multi-channel yet remarkably efficient ISC process is revealed by ultrafast femtosecond transient absorption (fs-TA) spectroscopy and theoretical calculation. The fs-TA verifies an exceptionally enhanced ISC efficiency (Φ_ISC = 91%) in iodine-substituted BODIPY (2I-BDP) which is further supported by the calculation results. This endows 2I-BDP with an ultrahigh singlet oxygen quantum yield (Φ_Δ = 88%), thus enabling a proof-of-concept application of highly efficient PDT in vivo under ultralow near-infrared light power density (10 mW cm⁻²). The in-depth understanding of ISC dynamics in organic near-infrared materials may provide valuable guidance in the designing of novel organic theranostic materials for clinical cancer treatment.