Nanochemistry and nanomaterials provide numerous opportunities for a new generation of photovoltaics with high solar energy conversion efficiencies at low fabrication cost. Quantum-confined nanomaterials and polymer–inorganic nanocomposites can be tailored to harvest sun light over a broad range of the spectrum, while plasmonic structures offer effective ways to reduce the thickness of light-absorbing layers. Multiple exciton generation, singlet exciton fission, photon down-conversion, and photon up-conversion realized in nanostructures, create significant interest for harvesting underutilized ultraviolet and currently unutilized infrared photons. Nanochemical interface engineering of nanoparticle surfaces and junction-interfaces enable enhanced charge separation and collection. In this review, we survey these recent advances employed to introduce new concepts for improving the solar energy conversion efficiency, and reduce the device fabrication cost in photovoltaic technologies. The review concludes with a summary of contributions already made by nanochemistry. It then describes the challenges and opportunities in photovoltaics where the chemical community can play a vital role.

Optical sensing plays an important role in theranostics due to its capability to detect hint biochemical entities or molecular targets as well as to precisely monitor specific fundamental psychological processes. Rare-earth (RE) doped upconversion nanoparticles (UCNPs) are promising for these endeavors due to their unique frequency converting capability; they emit efficient and sharp visible or ultraviolet (UV) luminescence via use of ladder-like energy levels of RE ions when excited at near infrared (NIR) light that are silent to tissues. These features allow not only a high penetration depth in biological tissues but also a high detection sensitivity. Indeed, the energy transfer between UCNPs and biomolecular or chemical indicators provide opportunities for high-sensitive bio- and chemical-sensing. A temperature-sensitive change of the intensity ratio between two close UC bands promises them for use in temperature mapping of a single living cell. In this work, we review recent investigations on using UCNPs for the detection of biomolecules (avidin, ATP, etc.), ions (cyanide, mecury, etc.), small gas molecules (oxygen, carbon dioxide, ammonia, etc.), as well as for in vitro temperature sensing. We also briefly summarize chemical methods in synthesizing UCNPs of high efficiency that are important for the detection limit.

Photovoltaic cells are able to convert sunlight into electricity, providing enough of the most abundant and cleanest energy to cover our energy needs. However, the efficiency of current photovoltaics is significantly impeded by the transmission loss of sub-band-gap photons. Photon upconversion is a promising route to circumvent this problem by converting these transmitted sub-band-gap photons into above-band-gap light, where solar cells typically have high quantum efficiency. Here, we summarize recent progress on varying types of efficient upconversion materials as well as their outstanding uses in a series of solar cells, including silicon solar cells (crystalline and amorphous), gallium arsenide (GaAs) solar cells, dye-sensitized solar cells, and other types of solar cells. The challenge and prospect of upconversion materials for photovoltaic applications are also discussed

A facilely prepared PVDF-HFP/SN separator homogenizes the Li⁺ flux through the formation of SN⋯PF₆⁻⋯Li⁺ structures between the SN agent and the electrolyte, resulting in even Li deposition and stable performances of Li metal batteries.

Ultrasmall upconversion (UC) nanoparticles with efficient multicolor photoluminescence (PL) are quite desirable for high contrast in vitro and in vivo bioimaging. Here, we present a simple and reproducible thermolysis approach to synthesize 3.7 nm sized lanthanide-doped YF₃ UC nanocrystals. The PL intensity of these ultrasmall nanoparticles was found to be about ten times brighter than that of 4.5 nm sized CaF₂ counterparts, which were reported to be one of the smallest efficient upconversion nanoparticles. We also showed that the color output of these nanocrystals can all be simply modulated by adjusting the sensitizer Yb³⁺ concentration. Moreover, to further enhance the PL output, a one nm thick epitaxial layer was grown onto the YF₃ nanocrystals. These lanthanide-doped ultrasmall upconversion YF₃ nanocrystals with modulated and enhanced multicolor output are ideal for a variety of in vitro and in vivo biological imaging applications.