Graphene quantum dots assisted photovoltage and efficiency enhancement in CdSe quantum dot sensitized solar cells

CdSe quantum dot sensitized solar cells （QDSCs） modified with graphene quantum dots （GQDs） have been successfully achieved in this work for the first time. Satisfactorily, the optimized photovoltage （Voc） of the modified QDSCs was approximately 0.04 V higher than that of plain CdSe QDSCs, consequently improving the photovoltaic performance of the resulting QDSCs. Served as a novel coating on the CdSe QD sensitized photoanode, GQDs played a vital role in improving Voc due to the suppressed charge recombination which has been confirmed by electron impedance spectroscopy as well as transient photovoltage decay measure- ments. Moreover, different adsorption sequences, concentration and deposition time of GQDs have also been systematically investigated to boost the power conversion efficiency （PCE） of CdSe QDSCs. After the coating of CdSe with GQDs, the resulting champion CdSe QDSCs exhibited an improved PCE of 6.59% under AM 1.5G full one sun illumination.

A Facile One-Step Synthesis of TiOe/Graphene Composites for Photodegradation of Methyl Orange

TiO2/graphene composite photocatalysts have been prepared by a simple liquid phase deposition method using titanium tetrafluoride and electron beam （EB） irradiation-pretreated graphene as the raw materials. The products were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The effects of varying the synthesis parameters such as graphene content, concentration of titanium tetrafluoride solution and irradiation dose were investigated. It was found that the preparation conditions had a significant effect on the structure and properties of the final products. The irradiated graphene was covered with petal-like anatase TiO2 nanoparticles, which were more uniform and smaller in size than those in products synthesized without EB irradiation-pretreated graphene. The photocatalytic activities of the products were evaluated using the photocatalytic degradation of methyl orange as a probe reaction. The results showed that the products synthesized using EB irradiation-pretreated graphene exhibited higher photocatalytic activities than those using graphene without EB irradiation pretreatment.

Synergistic anti-tumor therapy by a homotypic cell membranecloaked biomimetic nanocarrier with exceptionally potent activity against hepatic carcinoma

Hepatic carcinoma(HC)is the sixth most frequently occurring malignancies and the third leading cause of cancer death worldwide.Sepantronium bromide(YM155)is a small molecule inhibitor of survivin,which has broad-spectrum anticancer therapeutic effects in various xenograft models.However,several-day continuous infusion is required to achieve greater antitumor efficacy because of rapid elimination from the blood circulation.Herein,a SMMC-7721 cancerous cyto-membrane-cloaked drug delivery system(DDS)(named as iM7721@GQD-YM),was developed for co-encapsulation of YM155 and graphene quantum dots(GQDs).Cytomembrane coating endowed iM7721@GQD-YM with effective targeting for homologous HC cells,excellent biocompatibility and favorable immunocompatibility for in vivo application.Surface decoration of iRGD peptide further enhanced its tumor targeting activity by iRGD-integrin recognition.In addition,under the irradiation of near-infrared ray(NIR),GQDs can directly kill tumors through photothermal effect and cause cell membrane rupture,accurately releasing YM155 at tumor sites.The physicochemical properties,in vivo and ex vivo anti-tumor efficacy,and mechanisms of iM7721@GQD-YM nanoparticles(NPs)were systematically investigated in this work.The experimental results clearly indicate that the versatile biomimetic DDS holds great potential for the treatment of HC,which merits further investigation in both pre-clinical and clinical studies.