• Energy Research
• 7. Clean energy close
• 4. Education close
• Chinese Academy of Sciences close

The cyclohexanone-containing fullerene mono-adduct, abbreviated as CHOC60, was efficiently prepared through single-step Diels-Alder reaction with 2-(trimethylsilyloxy)-l,3-butadiene and fullerenes. After reduction and esterification, CHOC60 was further converted into cyclohexyl acetate functional fullerene mono-adduct, named as CHAC60, which showed excellent solubility in common organic solvents. P3HT-based bulk heterojunction organic solar cells (OSCs) were fabricated through a typical structure of ITO/PEDOT:PSS/P3HT:(CHOC60 or CHAC60)/Ca/Al. The composite ratios of P3HT and the fullerene derivatives were modified such as 1:0.5, 1:1 and 1:1.5 (w/w). The devices fabricated using CHOC60 or CHAC60 as acceptors achieved the power conversion efficiencies (PCEs) of 2.97% and 3.15%, respectively, which exhibited comparative photovoltaic performances with commercial PC61BM. Moreover, CHOC60-based devices significantly reduced the manufacturing cost by the simplified synthesis of CHOC60 with high yield and low fullerene consumption. The non-aromatic side chain radical CHOC60 and CHAC60 provide a new idea for the design of fullerene derivative acceptors.

Abstract. A global monthly evapotranspiration (ET) product without spatial-temporal gaps for 2000–2017 is delivered by using an energy balance (EB) algorithm and MODIS satellite data. It provides us with a moderate resolution estimate of ET without spatial-temporal gaps on a global scale. The model is driven by monthly remote sensing land surface temperature and ERA-Interim meteorological data. A global turbulent exchange parameterization scheme was developed for global momentum and heat roughness length calculation with remote sensing information. The global roughness length was used in the energy balance model, which uses monthly land-air temperature gradient to estimate the turbulent sensible heat, and take the latent heat flux as a residual of the available energy. This study produced an ET product for global landmass, at a monthly time step and 0.05-degree spatial resolution. The performance of ET data has been evaluated in comparison to hundreds flux sites measurements representing a broad range of land covers and climates. The ET product has a mean bias of 3.3 mm/month, RMSE value of 36.9 mm/month. The monthly ET product can be used to study the global energy and hydrological cycles at either seasonal or inter-annual temporal resolution.

Abstract Solar photovoltaic (PV) technology is widely regarded as a significant and sustainable renewable energy option to fight against climate change.Accordingly, it is important to explore the potential of greenhouse gases (GHGs) mitigation and temperature benefits by substituting PV-generated power for coal-fired electricity. This necessity becomes particularly clear given that China hascommitted itself to a carbon emissions peak around 2030. Based on an integrated energy-economy-environmental model and a simple climate response model, we reach the following conclusions: (1) By restraining the cumulative GHGs emissions space within 255 GtCO 2eq till 2050, PV solar promises to dominate GHGs mitigation, with the highest contribution reaching 64.67%. (2) Under the moderate emissions-control case, China will achieve its emissions peak target, with solar energy substitution relieving the nation׳s dependence on coal. (3) The highest radiative forcing and temperature benefits yieldedthrough replacing coal-generated power with solar power is around 20% and 11.05%, respectively. (4) Finally, it is not too costly to gain such benefits: at most, the accumulated economic cost would be 102.14 trillion Yuanuntil 2050, accounting for less than 3% of the accumulated GDP.

AbstractEnergy is the biggest crisis to humanity in the future. Nowadays, most of the energy used on earth comes from oil, gas and coal. According to the recent exploring and consuming rates, the energy will be exhausted in 50-100 years. Whether we can solve the crisis is closely related to the survival of humanity on the earth. The irradiation from the sun is the biggest energy source. Building PV power plant to utilize the energy from sun will be an only way to sustain the life cycle on the earth. However, the development of PV power plants require the huge supply of PV cell and the fabrication process may bring a quantity of pollution and waste, which is harmful to the environment. On the other hand, super large PV power plant will occupy huge land. If the land cannot be explored and used reasonably, this will not benefit the human life either. In this article, we address the discussions about the above problems and propose the initial suggestions about development trend of PV industry and the safety operation mode of super PV power plant.

The silicon vertical multi-junction (VMJ) solar cell has low costs and low series resistance, thus it has a good potential in concentration photovoltaics. However, there were few discussions about the thermal and electrical performance of silicon VMJ cell under non-uniform illumination. In this work, the thermal performance of silicon VMJ cell under 1D non-uniform illumination of 500 suns was calculated using finite element method first, and then the electrical performance of the cell was calculated using SPICE software based on the thermal simulation results. It was found that the mean temperature of the cell increased with the degree of non-uniform illumination when the area ratio of the sink to the cell was 500X, and the mean temperature changed few when the area ratio was 2500X. The efficiency of the cell did not decrease with the increase of the degree of non-uniform illumination when the area ratio was 500X, and the efficiency increased with the degree of non-uniform illumination when the area ratio was 2500X. Thus, the silicon VMJ cell had better performance than silicon planar junction cell under 1D non-uniform illumination of 500 suns.

CsPbBr3‐based perovskite solar cells possess both high humidity and temperature tolerance, and also have excellent long‐term stability in air, but the defect states in the bulk perovskite are always an obstacle for further improvement of their efficiency. Herein, a doping strategy is demonstrated in which AgBr is directly added to the precursor solution in the first step. An appropriate amount of Ag+ ion doping can passivate the defects in bulk or at grain boundaries, reduce the defect density of the film, and form a pinhole‐free film. Finally, the best power conversion efficiency of the solar cell reaches to 6.92% and exhibits a long‐term stability in a humid environment. This work provides a simple and effective method for improving the quality of CsPbBr3 film and the performance of CsPbBr3‐based perovskite solar cells.

Abstract In the present study, the thermal performance of a latent heat thermal energy storage device based on flat miniature heat pipe arrays with straight rectangular fins during the charging process is numerically investigated using porous media to reduce computational resources and time. Air is selected as the heat transfer fluid (HTF). The influence of a thermal storage unit (TSU) with one heat transfer component (HTC) on the melting rates of the phase change material (PCM) is simulated at different inlet temperatures and flow rates of HTF. The heat transfer between two HTCs that form a tandem is analyzed and compared, and the effect of different arrangements of the two HTCs on the charging process is then studied. Results indicate that the inlet temperature and the volume flow rate of the TSU influence the charging process. The average outlet temperature and charging power, which grow in a power function relationship with the volume flow rates, increase linearly with the inlet temperatures. The average charging power of the HTF through HTC-2 is reduced by approximately 63.71% compared with HTC-1 when the two HTCs form a tandem. The average charging power of the TSU with two HTCs connected in tandem is higher than that of the parallel TSU at the same inlet temperature and volume flow rate.

Abstract Significant efforts have been made to improve the performance of the Cu(In1-xGax)Se2 (CIGS) solar cells by tuning the band gap of the CIGS absorber to match it with the solar spectrum. However, the performance of the current record-holding CIGS solar cells is still far from theoretical expectations. Various researchers reported that the open circuit voltage (Voc) and the fill factor (FF) degrade in wide band gap CIGS solar cells. However, the limiting factors on further boosting the efficiency are still a matter of debate. In this study, we focus on tuning the properties of the interfacial layer between the rear contact and the wide-gap CIGS absorber to lower the contact resistance and recombination rate. Based on the numerical simulation using SCAPS (a solar cell capacitance simulator), we find that a MoO3 interfacial layer with high work function is more effective than its MoSe2 counterpart in reducing the back barrier, which in turn increases the Voc and the FF of the solar cell. We further predict that an overall efficiency of 24% can be achieved by reducing the back surface recombination and Schottky barrier with sub-micrometer a thick CIGS absorber. This work puts forward a strategy to improve the efficiency of wide band gap CIGS solar cells whilst reducing the raw materials consumption.