Indoor organic and perovskite photovoltaics(PVs)have been attracting great interest in recent years.The theoretical limit of indoor PVs has been calculated based on the detailed balance method developed by Shockley–Q...Indoor organic and perovskite photovoltaics(PVs)have been attracting great interest in recent years.The theoretical limit of indoor PVs has been calculated based on the detailed balance method developed by Shockley–Queisser.However,realistic losses of the organic and perovskite PVs under indoor illumination are to be understood for further efficiency improvement.In this work,the efficiency limit of indoor PVs is calculated to 55.33%under indoor illumination(2700 K,1000 lux)when the bandgap(E_(g))of the semiconductor is 1.77 eV.The efficiency limit was obtained on the basis of assuming 100%photovoltaic external quantum efficiency(EQ_(EPV))when E≥E_(g),there was no nonradiative recombination,and there were no resistance losses.In reality,the maximum EQEPV reported in the literature is 0.80–0.90.The proportion of radiative recombination in realistic devices is only 10^(−5)–10^(−2),which causes the open-circuit voltage loss(ΔV_(loss))of 0.12–0.3 V.The fill factor(FF)of the indoor PVs is sensitive to the shunt resistance(R_(sh)).The realistic losses of EQE_(PV),nonradiative recombination,and resistance cause the large efficiency gap between the realistic values(excellent perovskite indoor PV,32.4%;superior organic indoor PV,30.2%)and the theoretical limit of 55.33%.In reality,it is feasible to reach the efficiency of 47.4%at 1.77 eV for organic and perovskite photovoltaics under indoor light(1000 lux,2700 K)with V_(OC)=1.299 V,J_(SC)=125.33μA/cm^(2),and FF=0.903 when EQE_(PV)=0.9,EQE_(EL)=10^(−1),R_(s)=0.5Ωcm^(2),and R_(sh)=10^(4) kΩcm^(2).展开更多
A solar PV panel works with maximum efficiency only when it is operated around its optimum operating point or maximum power point.Unfortunately,the performance of the solar cell is affected by several factors like sun...A solar PV panel works with maximum efficiency only when it is operated around its optimum operating point or maximum power point.Unfortunately,the performance of the solar cell is affected by several factors like sun direction,solar irradiance,dust accumulation,module temperature,as well as the load on the system.Dust deposition is one of the most prominent factors that influence the performance of solar panels.Because the solar panel is exposed to the atmosphere,dust will accumulate on its surface,reducing the quantity of sunlight reaching the solar cell and diminishing output.In the proposed work,a detailed investigation of the performance of solar PV modules is carried out under the tropical climatic condition of Chennai,India,where the presence of dust particles is very high.The data corresponding to four different dust samples of various densities at four solar irradiation levels of 220,525,702,and 905 W/m^(2)are collected,and performance analysis is carried out.Based on the analysis carried out,the maximum power loss is found to be 73.51%,66.29%,65.46%,and 61.42%,for coal,sand,brick powder,and chalk dust respectively.Hence,it can be said that coal dust contributes to the maximum power loss among all four dust samples.Due to heat dissipation produced by dust deposition,the performance of solar PV modules is degraded as the temperature rose.展开更多
In recent years the photovoltaic community has witnessed the unprecedented development of perovskite solar cells(PSCs) as they have taken the lead in emergent photovoltaic technologies. The power conversion efficien...In recent years the photovoltaic community has witnessed the unprecedented development of perovskite solar cells(PSCs) as they have taken the lead in emergent photovoltaic technologies. The power conversion efficiency of this new class of solar cells has been increased to a point where they are beginning to compete with more established technologies. Although PSCs have evolved a variety of structures, the use of hole-transporting materials(HTMs) remains indispensable. Here, an overview of the various types of available HTMs is presented. This includes organic and inorganic HTMs and is presented alongside recent progress in associated aspects of PSCs, including device architectures and fabrication techniques to produce high-quality perovskite films. The structure, electrochemistry, and physical properties of a variety of HTMs are discussed, highlighting considerations for those designing new HTMs. Finally, an outlook is presented to provide more concrete direction for the development and optimization of HTMs for highefficiency PSCs.展开更多
China’s petroleum industry is monopolistic in its main business activities.However,the reasonability of this monopoly needs to be discussed according to its technical and economic characters.Research results show tha...China’s petroleum industry is monopolistic in its main business activities.However,the reasonability of this monopoly needs to be discussed according to its technical and economic characters.Research results show that the petroleum pipeline transportation business is naturally monopolistic while other businesses are competitive.Those business activities which can be open to competition but are in fact monopolistic are so owing to administrative order,and run inefficiently as a consequence.In order to improve productive efficiency and reduce efficiency losses,we propose three restructuring patterns of the petroleum industry-the Access Control Model,the Ownership Separation Model,and the Mutual-benefit Network Model.These three models have both advantages and disadvantages.Considering the prevailing practices in the petroleum industry in China,we think that the best choice is the Access Control Model.In order to improve restructuring effects of regulatory patterns,we design three differentiated regulatory policies,including differentiated entry regulation policies,differentiated price regulation policies,and differentiated distribution of different ownership enterprises policies.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52273180 and 51973074)the China Postdoctoral Science Foundation(Nos.2019M662614 and 2020M682404)the WNLO Funds for Innovation.
文摘Indoor organic and perovskite photovoltaics(PVs)have been attracting great interest in recent years.The theoretical limit of indoor PVs has been calculated based on the detailed balance method developed by Shockley–Queisser.However,realistic losses of the organic and perovskite PVs under indoor illumination are to be understood for further efficiency improvement.In this work,the efficiency limit of indoor PVs is calculated to 55.33%under indoor illumination(2700 K,1000 lux)when the bandgap(E_(g))of the semiconductor is 1.77 eV.The efficiency limit was obtained on the basis of assuming 100%photovoltaic external quantum efficiency(EQ_(EPV))when E≥E_(g),there was no nonradiative recombination,and there were no resistance losses.In reality,the maximum EQEPV reported in the literature is 0.80–0.90.The proportion of radiative recombination in realistic devices is only 10^(−5)–10^(−2),which causes the open-circuit voltage loss(ΔV_(loss))of 0.12–0.3 V.The fill factor(FF)of the indoor PVs is sensitive to the shunt resistance(R_(sh)).The realistic losses of EQE_(PV),nonradiative recombination,and resistance cause the large efficiency gap between the realistic values(excellent perovskite indoor PV,32.4%;superior organic indoor PV,30.2%)and the theoretical limit of 55.33%.In reality,it is feasible to reach the efficiency of 47.4%at 1.77 eV for organic and perovskite photovoltaics under indoor light(1000 lux,2700 K)with V_(OC)=1.299 V,J_(SC)=125.33μA/cm^(2),and FF=0.903 when EQE_(PV)=0.9,EQE_(EL)=10^(−1),R_(s)=0.5Ωcm^(2),and R_(sh)=10^(4) kΩcm^(2).
文摘A solar PV panel works with maximum efficiency only when it is operated around its optimum operating point or maximum power point.Unfortunately,the performance of the solar cell is affected by several factors like sun direction,solar irradiance,dust accumulation,module temperature,as well as the load on the system.Dust deposition is one of the most prominent factors that influence the performance of solar panels.Because the solar panel is exposed to the atmosphere,dust will accumulate on its surface,reducing the quantity of sunlight reaching the solar cell and diminishing output.In the proposed work,a detailed investigation of the performance of solar PV modules is carried out under the tropical climatic condition of Chennai,India,where the presence of dust particles is very high.The data corresponding to four different dust samples of various densities at four solar irradiation levels of 220,525,702,and 905 W/m^(2)are collected,and performance analysis is carried out.Based on the analysis carried out,the maximum power loss is found to be 73.51%,66.29%,65.46%,and 61.42%,for coal,sand,brick powder,and chalk dust respectively.Hence,it can be said that coal dust contributes to the maximum power loss among all four dust samples.Due to heat dissipation produced by dust deposition,the performance of solar PV modules is degraded as the temperature rose.
基金financial support from the Natural Science Foundation of China (grant numbers: 51661135021, 21606039, 91233201, and 21276044)
文摘In recent years the photovoltaic community has witnessed the unprecedented development of perovskite solar cells(PSCs) as they have taken the lead in emergent photovoltaic technologies. The power conversion efficiency of this new class of solar cells has been increased to a point where they are beginning to compete with more established technologies. Although PSCs have evolved a variety of structures, the use of hole-transporting materials(HTMs) remains indispensable. Here, an overview of the various types of available HTMs is presented. This includes organic and inorganic HTMs and is presented alongside recent progress in associated aspects of PSCs, including device architectures and fabrication techniques to produce high-quality perovskite films. The structure, electrochemistry, and physical properties of a variety of HTMs are discussed, highlighting considerations for those designing new HTMs. Finally, an outlook is presented to provide more concrete direction for the development and optimization of HTMs for highefficiency PSCs.
文摘China’s petroleum industry is monopolistic in its main business activities.However,the reasonability of this monopoly needs to be discussed according to its technical and economic characters.Research results show that the petroleum pipeline transportation business is naturally monopolistic while other businesses are competitive.Those business activities which can be open to competition but are in fact monopolistic are so owing to administrative order,and run inefficiently as a consequence.In order to improve productive efficiency and reduce efficiency losses,we propose three restructuring patterns of the petroleum industry-the Access Control Model,the Ownership Separation Model,and the Mutual-benefit Network Model.These three models have both advantages and disadvantages.Considering the prevailing practices in the petroleum industry in China,we think that the best choice is the Access Control Model.In order to improve restructuring effects of regulatory patterns,we design three differentiated regulatory policies,including differentiated entry regulation policies,differentiated price regulation policies,and differentiated distribution of different ownership enterprises policies.