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A low-cost and easy-to-construct dye-sensitized photoanode for water oxidation was prepared by co-loading a new triphenylamine donor-acceptor organic chromophore (D1) and a Co4O4 cobalt cubane-based water oxidation catalyst (CoF) on TiO2 thin films. As the first example of a molecular catalyst-based, noble metal-free, dye-sensitized photoanode, the electrode, TiO2|D1,CoF, produces a higher photocurrent than other noble metal-free, dye-sensitized photoanodes with a relatively high faradaic efficiency for O2 production. The success of the dyad system lies in retarded interfacial charge recombination and extended light absorption both of which take advantage of the pyridine anchor-functionalized chromophore. In addition, the CoF catalyst, decorated with hydrophobic aliphatic chains, serves as a protective layer for stabilizing the organic dyes on electrode surfaces. Transient absorption measurement suggests the accumulation of oxidative equivalents on CoF by electron transfer on the TiO2 surface. The results and design principles presented here demonstrate the use of molecular engineering as a powerful tool for the exploration of low-cost solar water-splitting devices., QC 20230124

The ultrafast excited-state relaxation dynamics of indolo[3,2-b]carbazole (ICZ) molecules were investigated in thin films and single crystals. In the ICZ film, singlet fission (SF) was directly observed both from the upper excited singlet states S-N within 480-850 fs and from the upper vibrational levels of the singlet state S-1 within 6-11 ps, which fully suppressed the intramolecular charge transfer (CT) process in S-1. In the ICZ crystal, the exciton relaxation through SF and polaron formation compete in the ultrafast timescale (<30 fs), which is accompanied by a thermally induced broadening of the S-1-S-N absorption band in the transient absorption spectra. The triplet-state lifetime is shortened from ICZ crystals (>1 ms) to films (2 mu s) due to SF with subsequent triplet-triplet annihilation, suggesting the impact of well-structured crystallinity and molecular packing on the exciton transport dynamics. The efficient SF together with well-characterized energy transfer and CT properties of ICZ solids extends the usage of ICZ-core-based organic materials in photovoltaic and electrochemical applications., QC 20210929

Femtosecond fluorescence up-conversion and transient absorption pump-probe setups are applied to study the relaxation dynamics of the lower and upper excited singlet electronic states in easy-to-make rubrene films. Upon 250 nm (4.96 eV) excitation, singlet fission was observed directly from S-2 state bypassing S-1 state within 30 fs i.e. breaking the classical Kasha rule. From the transient absorption measurements, polaron formation was also detected on the same time scale. Both singlet fission and polaron formation are accelerated from upper excited states compared with S-1 state. Our work shows that rubrene films with low degree of crystallinity could display efficient singlet fission, notably in the case of excitation to upper lying electronic states. This can strongly expand the applications of rubrene in organic electronics. Moreover, our results will provide a new direction for synthesizing novel materials with optimized excited state properties for organic photovoltaic applications., QC 20210302

Excited-state dynamics in a strong charge-transfer (perylene)(3)-7,7,8,8-tetracyanoquinodimethane (P3T1) single-crystal system was studied by use of femtosecond transient absorption and upconversion time-resolved fluorescence techniques. Charge separation within 0.6-1.2 ps and subsequent recombination within 6.6-12 ps was demonstrated. Moreover, the excited-state dynamics in the P3T1 crystal was found to depend on excitation energies. Excitation of upper excited electronic states (4.96 eV) leads to efficient direct population of perylene triplet states via singlet fission. At lower excitation photon energies, enhancement of triplet state formation via intersystem crossing as a result of efficient spin-orbit charge transfer was observed. By varying the excitation wavelength, the performance of optoelectronic devices can be tuned, i.e., photon absorption, free carrier transfer, mobility, and recombination., QC 20200717

Relaxation pathways of upper excited electronic states of malachite green (MG) in ethanol and in films are studied by steadystate and time-resolved spectroscopic techniques. In contrast to ethanol, where MG emits weak short-lived spectrally well separated S-2 and S-1 fluorescence with the lifetimes similar to 0.3 and similar to 0.9 ps, MG films show a much stronger broadband fluorescence within 430-700 nm, revealing multiexponential kinetics with the characteristic decay times tau(1) approximate to 1 ps, tau(2) approximate to 10 ps, tau(3) approximate to 0.05-0.8 ns, and tau(4) approximate to 2-3 ns. By the analysis of spectroscopic responses of MG in ethanol and in films as well as by theoretical modeling, we demonstrate that significant increase of fluorescence lifetimes and substantial enhancement of fluorescence intensity in MG films are stipulated by the decrease of efficiency of the S-2 -> S-1 and S-1 -> S-0 internal conversion, which in turn is caused by hindrance of rotation of MG's phenyl rings controlling the S-2/S-1 and S-1/S-0 conical intersections. These findings indicate that MG films may become promising non-Kasha materials (with reasonable S-2 emission) with numerous photophysical and photochemical applications., QC 20210302

Singlet fission directly from the upper excited vibrational and electronic states of cofacial perylene dimers, bypassing the relaxed state S-1, was detected within 50 fs. This process competes well with vibrational cooling in S-1 (4.7-7.0 ps) and S-2 -> S-1 internal conversion (380 fs). The singlet fission has the energy threshold E = 3.06 eV. Other competitive relaxation processes are excimer and dimer cation formation on an ultrafast time scale. Excitation to higher energy levels (4.96 eV) leads to a higher efficiency of singlet fission., QC 20190814

Wenjun Ni,1,2 Erlin Song,1 Mancheng Gong,3 Yongxiang Li,4 Jie Yao,5 Ruihua An1 1Department of Urology Surgery, The First Affiliated Hospital of Harbin Medical University, 2Department of Urology, Heilongjiang Provincial Hospital, Harbin, Heilongjiang, 3Department of Urology, The People’s Hospital of Zhongshan, Zhongshan, Guangdong, 4Department of Urology, The People’s Hospital of Weifang, Weifang, Shandong, 5Department of Oncology, the 161th Hospital of PLA, Wuhan, Hubei, People’s Republic of China Abstract: Renal cell carcinoma (RCC) is a common type of kidney cancer. Normally, surgical treatment can prolong life, but only for patients with early stage tumors. However, it is difficult for early detection strategies to distinguish between benign and malignant kidney tumors. Therefore, potential biomarkers for early diagnosis and prognosis of RCC are needed. Intriguingly, mounting evidence has demonstrated that many long noncoding RNAs (lncRNAs) are strongly linked to cancers. Indeed, promising RCC-associated lncRNA biomarkers have also been identified. However, the functional and prognostic roles of the antisense (AS) serum deprivation response (SDPR) lncRNA (SDPR-AS) in RCC remain largely unknown. The aims of this study were to investigate the expression and prognostic relevance of SDPR-AS in RCC. We uncovered the downregulated expressions of both lncRNA SDPR-AS and its protein-coding gene, SDPR, in RCC tissues compared to the matched normal tissues. Furthermore, SDPR-AS and SDPR expressions were positively correlated. Overexpression and knockdown experiments suggested that SDPR-AS and SDPR were coregulated in RCC cell lines. In addition, overexpression of SDPR-AS suppressed cell migration and invasion, but not cell growth. Furthermore, expression of SDPR-AS was associated with tumor differentiation and lymphatic metastasis. Kaplan–Meier survival and log-rank tests demonstrated the association of elevated expression of SDPR-AS