向日葵型跟踪太阳智能发电装置的研制

针对现有太阳能光伏发电装置能量转换效率较低的缺陷,设计开发了一种光机电结合的微功耗智能太阳跟踪装置。该装置采用了不同于传感器方式的定时跟踪电路,省去传感器和相关电路的能耗,充分利用了微电脑中最省电的休眠工作模式,并利用最小的功耗驱动太阳能电池组件跟踪太阳,以大幅度提高太阳能的转换效率。考虑到全国地域的差异该装置设计了用户自行设置时间等功能。通过两种太阳电池实验比较,证明该装置能大幅度提高太阳能的转换效率。

3D surfactant-dispersed graphenes as cathode interfacial materials for organic solar cells

Graphene dispersions in low-boiling-point green solvents have wide applications in coatings,conducting inks,batteries,electronics and solar cells.Two three-dimensional(3D)cathode interfacial materials(CIMs)(1,3,5,7,9,11,13,15-octa-(9-bis(30-(N,N-dimethylamino)propyl)-2,7-fluorene)-vinylpentacyclo-octasiloxane)(POSSFN)and(1,3,5,7-tetra-(9-bis(30-(N,N-dimethylamino)propyl)-2,7-fluorene)-adamantane)(ADMAFN)are excellent surfactants for dispersing graphene in ethanol at the concentration of 0.97–1.18 mg mL−1,in agreement with their calculated large adsorption energies on graphene.The results of electron spin resonance,Raman,scanning Kelvin probe microscopy and X-ray photoelectron spectroscopy measurements indicate that the amino groups could n-dope graphene or form dipole interaction with graphene.The two 3D-surfactant-based graphene composites(POSSFN-G and ADMAFN-G)can work as high-performance CIMs in organic solar cells(OSCs),which improve the power conversion efficiency(PCE)of the OSCs based on PM6:Y6 to 15.9%–16.1%.ADMAFN forms dipole interaction with graphene in ADMAFN-G and the composite CIM delivers high PCE of 16.11%in the OSCs,while POSSFN forms n-doped composition with graphene in POSSFN-G which works well as thicker CIM film in the OSCs.

15.3% efficiency all-small-molecule organic solar cells enabled by symmetric phenyl substitution

Synergistic optimization of donor-acceptor blend morphologyis a hurdle in the path of realizing efficient non-fullerene small-molecule organic solar cells(NFSMOSCs)due to the anisotropic conjugated backbones of both donor and acceptor.Therefore,developing a facile molecular design strategy to effectively regulate the crystalline properties of photoactive materials,and thus,enable the optimization of blend morphology is of vital importance.In this study,a new donor molecule B1,comprising phenyl-substituted benzodithiophene(BDT)central unit,exhibits strong interaction with the non-fullerene acceptor BO-4 Cl in comparison with its corresponding thiophene-substituted BDT-based material,BTR.As a result,the B1 is affected and induced from an edgeon to a face-on orientation by the acceptor,while the BTR and the acceptor behave individually for the similar molecular orientation in pristine and blend films according to grazing incidence wide angle X-ray scattering results.It means the donor-acceptor blend morphology is synergistically optimized in the B1 system,and the B1:BO-4 Cl-based devices achieve an outstanding power conversion efficiency(PCE)of 15.3%,further certified to be 15.1%by the National Institute of Metrology,China.Our results demonstrate a simple and effective strategy to improve the crystalline properties of the donor molecule as well as synergistically optimize the morphology of the all-small-molecule system,leading to the high-performance NFSM-OSCs.

Effect of concomitant anti-solvent engineering on perovskite grain growth and its high efficiency solar cells

The grain boundaries and interface properties in the active layers of perovskite solar cells(PSCs)are important factors affecting the performances of the devices.In this work,a simple and fast concomitant annealing process is established by inducing the secondary growth of the grains using the anti-solvent o-dichlorobenzene(o-PhCl2)or chlorobenzene(PhCl)to suppress the volatilization of solvent molecules during the FA0.80MA0.15Cs0.05Pb(I0.85Br0.15)3(FA,CH5N2+,formamidine;MA,CH3NH3+,methylamine)film annealing procedure.The effects of anti-solvent molecules on the phase transformation,grain boundary fusion and morphology evolution of perovskite films are systematically investigated by X-ray diffraction(XRD)and scanning electron microscopy(SEM).The results indicate that anti-solvent molecules can inhibit solvent evaporation in the active layers and promote crystallite dissolution and ordered secondary growth along the surfaces of large grains.That can promote the formation of large grains and the passivation of surface defects,and can be favorable for the separation and transportation of photocarriers in the active layer.Consequently,the power conversion efficiency(PCE)of PSCs can be effectively improved,with a PCE of 20.72%being achieved by a secondary growth perovskite film optimized with o-PhCl2.Moreover,the efficiency remains at 85%of its initial value after 2400 h of treatment in a natural indoor environment with a relative humidity of 45±5%.

Stereomeric effects of bisPC_(71)BM on polymer solar cell performance

Two stereomers of bisadduct analogues of [6, 6]-phenyl-C71-butyric acid methyl ester （bisPC71BM） were synthesized and their geometrical structures with cis- or trans-configuration were identified by X-ray crystallogra- phy. Although both of the bisPC71BM have similar spec- trometric and electrochemical properties, the spatial orientation of the two addition groups on C7o has impact on crystal packing and molecular assembly of bisPC71BM isomers and, in turn, photovoltaic performance in polymer solar cell based on poly（3-hexylthiophene） （P3HT） （with power conversion efficiency of 1.72 % and 1.84 % for the solar cells involving cis- and trans-bisPC71BM, respec- tively）. Although the power conversion efficiency remains to be improved, this work exemplifies that the photovoltaic properties of fullerene-based electron acceptors areinfluenced by aggregation of the stereomeric molecules and thus extends the guidelines for rational design of efficient fullerene acceptor.

Photovoltaic efficiency enhancement of polycrystalline silicon solar cells by a highly stable luminescent film

Si-based solar cells have dominated the entire photovoltaic market,but remain suffering from low power conversion efficiency(PCE),partly because of the poor utilization of ultraviolet(UV)light.Europium(III)(Eu^3+)complexes with organic ligands are capable of converting UV light into strong visible light,which makes them ideal light converter to increase the efficiency of solar cells.However,the low stability of such complexes seriously hampers their practical applications.In this work,we report a highly stable and luminescent ethylene-vinyl acetate(EVA)copolymer film consisting of a Eu^3+complex as a down-shift material,Eu(ND)4 CTAC(ND=4-hydroxy-2-methyl-1,5-naphthyridine-3-carbonitrile,CTAC=hexadecyl trimethyl ammonium chloride),coating of which onto the surface of large area polycrystalline silicon solar cells(active area:110 cm^2)results in an increase of PCE from 15.06%to 15.57%.Remarkable stability of the luminescent film was also demonstrated under lightsoaking test for 500 h,and no obvious luminescence degradation can be observed.The remarkable enhancement of the conversion efficiency by 0.51%absolute on such a large active area,together with the high stability of the luminescent film,demonstrates a prospect for the implementation of the films in photovoltaic industry.

Theoretical insight into the stereometric effect of bisPC71BM on polymer cell performance

It has been experimentally demonstrated that the stereometric packings of two new bisPC_(71) BM isomers have an important impact on the power conversion efficiency of organic solar cells. Here, a theoretical investigation is made to reveal the mechanism behind from detailed photophysical processes in performed cells. The results show that the crystal packings of isomers affect the electron mobilities dominantly from the electronic coupling for electron transfer, and the trends of calculated mobilities are consistent with experimental measurements although the magnitudes are obviously larger. For the performed cells from two isomers with poly(3-hexylthiophene) as a donor, it is found that the exciton dissociation yields are also different, manifesting that stereometric packings essentially control the cell efficiency via both electron mobilities and exciton dissociation. Furthermore,the reasons for low cell efficiencies are analyzed, and possible improvements are suggested.

Thiamine additive engineering enables improved film formation towards high efficiency and moisture stability in perovskite solar cells

Perovskite solar cells(PSCs)attract widespread research interest due to their exceptional properties.However,the instability of the perovskite layer,especially the moisture instability,and existing defects seriously restrict the performance and limit the development of PSCs towards commercialization.Herein,we fabricate moisture-stable and efficient PSCs by incorporating a thiamine(THM)additive into a lead iodide(PbI_(2))precursor using a two-step spin-coating method.This strategy enables a better interaction between the THM additive and PbI_(2).Then,a higher energy barrier is produced when the material reacts with A-site cations to form perovskite crystals,resulting in larger grains and better-quality perovskite films.Through optimization of the concentration of the THM additive,the optimal perovskite achieves improved moisture stability and decreased trap states;thus,the corresponding unencapsulated devices achieve a remarkable power conversion efficiency(PCE)of 21.40%and maintain>92%of their initial PCE after 180 h in ambient air(~50%humidity).The excellent performance is mainly attributed to the fact that THM promotes crystal growth and passivates defects in perovskite films.