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Quantum dot (QD) photovoltaic devices are attractive for their low-cost synthesis, tunable band gap and potentially high power conversion efficiency (PCE). However, the experimentally achieved efficiency to date remains far from ideal. Here, we report an in-situ fabrication and investigation of single TiO2-nanowire/CdSe-QD heterojunction solar cell (QDHSC) using a custom-designed photoelectric transmission electron microscope (TEM) holder. A mobile counter electrode is used to precisely tune the interface area for in situ photoelectrical measurements, which reveals a strong interface area dependent PCE. Theoretical simulations show that the simplified single nanowire solar cell structure can minimize the interface area and associated charge scattering to enable an efficient charge collection. Additionally, the optical antenna effect of nanowire-based QDHSCs can further enhance the absorption and boost the PCE. This study establishes a robust 'nanolab' platform in a TEM for in situ photoelectrical studies and provides valuable insight into the interfacial effects in nanoscale solar cells.

Quantum dot (QD) photovoltaic devices are attractive for their low-cost synthesis, tunable band gap and potentially high power conversion efficiency (PCE). However, the experimentally achieved efficiency to date remains far from ideal. Here, we report an in-situ fabrication and investigation of single TiO2-nanowire/CdSe-QD heterojunction solar cell (QDHSC) using a custom-designed photoelectric transmission electron microscope (TEM) holder. A mobile counter electrode is used to precisely tune the interface area for in situ photoelectrical measurements, which reveals a strong interface area dependent PCE. Theoretical simulations show that the simplified single nanowire solar cell structure can minimize the interface area and associated charge scattering to enable an efficient charge collection. Additionally, the optical antenna effect of nanowire-based QDHSCs can further enhance the absorption and boost the PCE. This study establishes a robust 'nanolab' platform in a TEM for in situ photoelectrical studies and provides valuable insight into the interfacial effects in nanoscale solar cells.

The ubiquitin C-terminal hydrolase (UCH) and ubiquitin-specific processing protease (UBP) protein families both function in protein deubiquitination, playing important roles in a wide range of biological processes in animals, fungi, and plants. Little is known about the functions of these proteins in rice (Oryza sativa), and the numbers of genes reported for these families have not been consistent between different rice database resources. To further explore their functions, it is necessary to first clarify the basic molecular and biochemical nature of these two gene families. Using a database similarity search, we clarified the numbers of genes in these two families in the rice genome, examined the enzyme activities of their corresponding proteins, and characterized the expression patterns of all OsUCH and representative OsUBP genes. Five OsUCH and 44 OsUBP genes were identified in the rice genome, with four OsUCH proteins and 10 of 16 tested representative OsUBP proteins showing enzymatic activities. Two OsUCHs and five OsUBPs were found to be preferentially expressed in the early development of rice stamens. This work thus lays down a reliable bioinformatic foundation for future investigations of genes in these two families, particularly for exploring their potential roles in rice stamen development.

Recent observations of the long-lasting nonlinear signals in a variety of light-harvesting complexes have initiated an active debate on the origin of long-lived coherence in the biological systems. In this work we show that disorder of site energy can induce a long-lived electronic coherence between two chromophores in a strongly coupled dimer system, in addition to the ensemble dephasing effect. This phenomenon is physically explained as the correlated fluctuation of excitons with the equal delocalization on two sites, when the site-energy distributions overlap to give resonance. Using the integrated two-color coherence photon echo signal as an example, we show that the coherence in such a system exhibits a biexponential decay with a slow component with a lifetime of hundreds of femtoseconds and a rapid component with a lifetime of tens of femtoseconds. The current result provides a possible microscopic basis for the electronic coherence to be the origin of the long-lived coherence signals to be considered along with other recently proposed mechanisms.

Recent observations of the long-lasting nonlinear signals in a variety of light-harvesting complexes have initiated an active debate on the origin of long-lived coherence in the biological systems. In this work we show that disorder of site energy can induce a long-lived electronic coherence between two chromophores in a strongly coupled dimer system, in addition to the ensemble dephasing effect. This phenomenon is physically explained as the correlated fluctuation of excitons with the equal delocalization on two sites, when the site-energy distributions overlap to give resonance. Using the integrated two-color coherence photon echo signal as an example, we show that the coherence in such a system exhibits a biexponential decay with a slow component with a lifetime of hundreds of femtoseconds and a rapid component with a lifetime of tens of femtoseconds. The current result provides a possible microscopic basis for the electronic coherence to be the origin of the long-lived coherence signals to be considered along with other recently proposed mechanisms.