Low-grade thermal energy is abundantly available in the form of waste heat or in the environment.1, 2Current technologies using liquid-based thermo-electrochemical cells (TECs) is both cost-effective and scalable for low-grade heat harvesting, and their temperature coefficient (mV/K) is one order of magnitude higher than that of solid-state thermoelectrics.3, 4, 5The research on TECs has mainly focused on the exploit of thermal gradient or thermal cycle, but the potential of these approaches has been limited by the poor energy conversion efficiency or the need of external electricity. We invent a new direct thermal charging cell (DTCC) for low-grade-heat-to-electricity conversion under an isothermal condition without the aid of the thermal gradient across two electrodes or the thermal cycle.6 The DTCC consists of graphene oxide (GO)/platinum nanoparticles (PtNPs) cathode and polyaniline (PANI) anode and an aqueous Fe2+/Fe3+ electrolyte, which can be thermally charged in the open circuit condition. Under isothermal operation, the pouch cell configuration of DTCC with a short distance between two electrodes can be employed for improving electrolyte conductance and rapid heating. Notably, the thermal voltage is generated based on thermo-pseudocapacitive reaction at the GO-electrolyte interface, demonstrating a very high temperature coefficient of 5.0 mV/K and the DTCC exhibits the energy conversion efficiency of 5.19% at 70oC (39.6% of Carnot efficiency). The great applicability of this new thermo-electrochemical system has been demostrated on supplying power for an electrochromic smart window by immerimg DTCCs in a hot water and lightening up an organic light emitting diode by placing DTCCs on a running compressor.
Viktoriia Osipova is a second-year master student of ITMO University in Saint -Petersburg, her major is “Physics and technology of nanostructures”.
Over the past three decades quantum dots (QDs) have become one of the leading lighting materials with efficient and tunable emission. A potential candidate for the replacement of well-studied CdSe and PbS is the quantum dots of ternary compounds such as AgInS2 (AIS) and CuInS2 (CIS) due to the absence of toxic heavy metals. The unique optical properties of ternary QDs, such as high extinction coefficients, the ability to control the luminescence wavelength by changing the size and composition of the nanoparticles, high quantum yield (QY), photostability and long decay times (~ hundreds of nanoseconds) make them promising alternatives for organic dyes and ideal materials for innovative biomedical tools and applications.
The excellent optical properties of t-QDs make them potential candidates in donor/acceptor systems for spectrally and time-resolved FRET detection schemes. Concerning this, the aim of our research was to investigate resonance energy transfer in a system of interacting water-soluble ternary quantum dots AgInS2/ZnS and organic dyes with a help of spectral luminescent methods.
As a result, effective non-radiative energy transfer was demonstrated in nanomaterials formed by charged AgInS2/ZnS triple quantum dots (donor) and a dye molecule (acceptor) embedded on polymer microspheres using polymer layer-by-layer method of coating. As the result selected organic dyes exhibit significantly increased luminescence decay times in complexes with QDs, which can be utilized for the time-resolved cell imaging and flow cytometry.