Excellent Passivation Research Articles

Electronic Characteristics of Ultra‐Thin Passivation Layers for Silicon Photovoltaics

AbstractSurface passivating thin films are crucial for limiting the electrical losses during charge carrier collection in silicon photovoltaic devices. Certain dielectric coatings of more than 10 nm provide excellent surface passivation, and ultra‐thin (<2 nm) dielectric layers can serve as interlayers in passivating contacts. Here, ultra‐thin passivating films of SiO2, Al2O3, and HfO2 are created via plasma‐enhanced atomic layer deposition and annealing. It is found that thin negatively charged HfO2 layers exhibit excellent passivation properties—exceeding those of SiO2 and Al2O3—with 0.9 nm HfO2 annealed at 450 °C providing a surface recombination velocity of 18.6 cm s−1. The passivation quality is dependent on annealing temperature and layer thickness, and optimum passivation is achieved with HfO2 layers annealed at 450 °C measured to be 2.2–3.3 nm thick which give surface recombination velocities ≤2.5 cm s−1 and J0 values of ≈14 fA cm−2. The superior passivation quality of HfO2 nanolayers makes them a promising candidate for future passivating contacts in high‐efficiency silicon solar cells.

Enhancing Performance and Stability of Perovskite Solar Cells through Surface Defect Passivation with Organic Bidentate Lewis Bases.

Organic Lewis bases [2,2′-bipyridine (BPY), 4-hydroxy-1,5-naphthyridine-3-carbonitrile (DQCN), and thenoyltrifluoroacetone (TTFA)] with bi-coordination sites of N and O were employed as perovskite surface defect passivants to address the efficiency and stability issues of perovskite solar cells (PSCs), with typical phenethylammonium iodide (PEAI) and piperazinium iodide (PI) passivants as reference. The surface properties of the perovskite films before and after passivation were characterized by Fourier-transform infrared, ultraviolet–visible, photoluminescence (PL), and time-resolved PL spectroscopy, X-ray diffraction, ultraviolet photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy. The characterizations reveal that BPY, DQCN, or TTFA forms coordination bonds with exposed “Pb2+”, leading to a slight decrease in the highest occupied molecular orbital or lowest unoccupied molecular orbital energy level and bandgap. These passivants (especially TTFA) can passivate the perovskite surface defects to inhibit non-radiative recombination while having almost no influence on the grain size and surface morphology. Utilizing the passivated perovskite as the light absorption layer, solar cells with an inverted configuration of indium tin oxide/NiOx/passivated MAPbClxI3–x/C60/BCP/Ag have been fabricated, and power conversion efficiencies of 19.22, 17.85, 16.49, 16.31, and 17.88% have been achieved from PEAI, PI, BPY, DQCN, and TTFA, respectively. All the device performance based on passivated perovskite is superior to that of the control (15.75%) owing to the reduced carrier recombination. The device from TTFA exhibits almost comparable efficiency to that of PEAI and PI controls, indicating that TTFA has an equal excellent passivation effect to state-of-the-art PEAI and PI. Furthermore, the devices based on BPY, DQCN, and TTFA show superior long-term stability with an efficiency loss of only 13.2, 16.7, and 12.9%, respectively, after being stored for 40 days in a ∼12% humidity, low-oxygen level environment, which is 45.4, 38.8, and 44.4% for the control, PEAI, and PI devices, respectively, primarily due to the improved hydrophobicity of the perovskite surface. Our results demonstrate that it is feasible to achieve high-efficiency and long-term-stable perovskite solar cells via selecting the appropriate molecules to passivate perovskite surface defects.

Performance promotion of aluminum oxide capping layer through interface engineering for tunnel oxide passivating contacts

High-efficiency silicon solar cells depend on passivating contact structure to decrease recombination losses at the crystalline silicon (c-Si) surface and the interface of metal/Si contact. Tunnel oxide passivating contact (TOPCon) technology is one of these structures, in which heavily doped poly-Si is placed over a SiO x layer grown directly on the c-Si wafer. The passivation performance can be further improved by depositing a thin aluminum oxide (AlO x ) layer on one side of the symmetric cell structure, which is attributed to the reduced interfacial defects, facilitated formation of carrier collector layer, and excellent field-effect passivation. Atomic layer deposition (ALD) may be utilized to produce high-quality and pinhole-free AlO x capping layers due to its controllability, homogeneity, and conformality. However, insufficient substrate surface activity is a challenge faced in AlO x deposition because it can impair Al(CH 3 ) 3 nucleation, resulting in an island-like growth over the first few ALD cycles, ultimately deteriorating the passivation effect of AlO x . In this study, we optimized the deposition process of ALD AlO x through a series of single-factor experiments. Subsequently, alternative substrate treatment methods were tested to compare the performance. In particular, we proposed a two-step interface engineering process (chemical mechanical polishing + RCA SC-2 treatment) to enhance the comprehensive performance of the ALD AlO x layer, achieving a high iV OC of 726 mV and low J 0 of 5.4 fA/cm 2 , compared with a reference poly-Si/c-Si passivating contact ( iV OC = 703 mV, J 0 = 19.4 fA/cm 2 ). The result was interpreted in terms of gradually improving substrate surface quality and wettability, together with the gradually decreasing thickness of the interfacial oxide layer. The circumvent of the island growth mode improved the growth quality of the subsequent film, effectively compressed the ALD cycle needed for stable growth, and enhanced the passivation property. Altogether, the present data may guide further efforts to obtain high-efficiency silicon-based solar cells by arising the interface engineering. • The optimum ALD AlO x process parameters are determined to optimize the AlO x coating process for industrial production. • A novel two-step interface engineering process (CMP + RCA SC-2 treatment) is proposed. • The overall passivation quality of the AlO x capped symmetric structure can be improved and the ρ c can be reduced simultaneously.

Over 16% efficiency organic/nanostructured Si heterojunction solar cells with a p-doped organic small molecule layer

Organic/nanostructured Si hybrid solar cells have achieved high power conversion efficiency (PCE) and short-circuit current density ( J SC ), due to the excellent light harvesting ability of nanostructured Si. However, the separation of carriers is mainly affected by the low work function of PH1000-type PEDOT:PSS, resulting in poor open circuit voltage ( V OC ). In this work, an efficient and stable MoO 3 -doped copper phthalocyanine-3,4′,4″,4‴-tetra-sulfonated acid tetra sodium salt (TS-CuPc) organic small molecule film was introduced between the heterojunction interfaces. The photogenerated carrier separation is promoted by the enhanced built-in potential ( V bi ) owing to the high work function of TS-CuPc:MoO 3 , which also suppresses the carrier recombination at the surface of nanostructured Si. As a result, for PEDOT:PSS/nanostructured Si photovoltaic devices, the PCE was greatly improved from 14.15% to 16.09%. The excellent charge separation properties and interface passivation effect enable efficient devices to demonstrate the vast potential of this new type of interlayer in photovoltaic applications. • The p-type doping increases the work function of TS-CuPc films. • The interlayer substantially improves charge separation at the Si/organic interface. • The device efficiency is as high as 16.09%, and V OC and FF are improved overall.

Low Cost, Al2O3 and ZrAlOx Stack Passivation by Spray Pyrolysis for Highly Stable Amorphous InGaZnO Thin‐Film Transistors

AbstractA stack passivation by spray pyrolysis is demonstrated for high performance and stable amorphous indium‐gallium‐zinc‐oxide (a‐IGZO) thin‐film transistors (TFTs). The device performances and stabilities of a‐IGZO TFTs are compared with single zirconium‐aluminium‐oxide (ZAO), aluminium oxide (Al2O3), and stack ZAO/Al2O3 and Al2O3/ZAO passivation layers. The a‐IGZO TFTs with Al2O3/ZAO stack exhibit high performance and excellent stabilities under electrical, thermal, and environmental tests with negligible threshold voltage shift. The origin of the device performances and improved stabilities are analyzed using X‐ray photoelectron spectroscopy and high‐resolution transmission electron microscopy analyses. It is found that the Zr elements diffuse into the a‐IGZO channel when ZAO is directly deposited on the a‐IGZO, resulting in the deterioration of the device performance. It is also found that the Al2O3 single layer on top of the a‐IGZO cannot protect the back‐channel from moisture diffusion. But a thin Al2O3 layer on top of the TFTs can protect the diffusion of Zr elements from ZAO into the a‐IGZO channel and enhances the performance and stabilities. Therefore, the low cost, Al2O3/ZAO stack by spray pyrolysis on the sputtered a‐IGZO can be an excellent passivation for highly stable metal‐oxide TFTs.

Comparing the Gettering Effect of Heavily Doped Polysilicon Films and Its Implications for Tunnel Oxide‐Passivated Contact Solar Cells

In addition to excellent surface passivation and carrier selectivity, the structure based on the heavily doped polysilicon layer on an ultrathin silicon oxide interlayer also demonstrates strong impurity gettering effects. Herein, the gettering strength of a range of phosphorus‐ or boron‐doped polysilicon films from different fabrication techniques is assessed and compared. Iron, one of the most common metallic impurities in silicon, is used as a tracer impurity to quantify the gettering strength (segregation coefficient). A comparison of the experimental results to the literature, combined with measurements of the electrically active and inactive dopant concentrations, enables us to suggest the main gettering mechanisms in different polysilicon films. The differences in the segregation coefficients of the phosphorus‐doped polysilicon films for iron are within one order of magnitude, in spite of their different combinations of gettering mechanisms. On the other hand, boron‐doped polysilicon films show a large variation in their gettering effects, although the predominant gettering mechanisms are all attributed to electrically inactive boron, according to the current understanding of the gettering mechanisms from the literature. Finally, the impact of different polysilicon gettering effects on the efficiency of tunnel oxide‐passivated contact (TOPCon) cells is simulated and discussed.

Experimental and Numerical Simulation of Molybdenum Oxide Films with Wide Bandgap and High Work Function for Carrier-Selective Contact Solar Cells

In silicon heterojunction (SHJ) solar cells, a wide bandgap material with a high work function is widely used as the hole extraction pathway to attain high efficiency. We introduced a molybdenum oxide (MoOx) film as an effective hole-transfer layer in carrier selective contact (CSC) solar cells by virtue of its wide bandgap along with high work function. The passivation characteristics, optical and electrical properties of MoOx films were investigated by differing thickness and work function. The combination of 6 nm hydrogenated intrinsic amorphous silicon (a-Si:H(i)) and 7 nm thermally evaporated MoOx passivation layers provides excellent passivation properties, reduces carrier recombination, and improves the cell performance. The synthesized CSC solar cells showed promising results, with an open-circuit voltage (Voc) of 708 mV, short-circuit current (Jsc) = 37.38 mA cm−2, fill factor (FF) = 74.59%, and efficiency (η) = 19.75%. To justify the obtained result, an AFORS HET simulation was conducted based on the experimental results. The high work function and wide bandgap MoOx/c-Si(n) interface developed a considerable built-in potential and suppressed the electron–hole pair recombination mechanism. The CSC solar cell’s simulated performance was enhanced from 1.62 to 23.32% by varying the MoOx work function (ΦMoOx) from 4.5 to 5.7 eV.

Raytracing Modelling of Infrared Light Management Using Molybdenum Disulfide (MoS2) as a Back-Reflector Layer in a Silicon Heterojunction Solar Cell (SHJ).

The silicon heterojunction solar cell (SHJ) is considered the dominant state-of-the-art silicon solar cell technology due to its excellent passivation quality and high efficiency. However, SHJ’s light management performance is limited by its narrow optical absorption in long-wave near-infrared (NIR) due to the front, and back tin-doped indium oxide (ITO) layer’s free carrier absorption and reflection losses. Despite the light-trapping efficiency (LTE) schemes adopted by SHJ in terms of back surface texturing, the previous investigations highlighted the ITO layer as a reason for an essential long-wavelength light loss mechanism in SHJ solar cells. In this study, we propose the use of Molybdenum disulfide (MoS2) as a way of improving back-reflection in SHJ. The text presents simulations of the optical response in the backside of the SHJ applying the Monte-Carlo raytracing method with a web-based Sunsolve high-precision raytracing tool. The solar cells’ electrical parameters were also resolved using the standard electrical equivalent circuit model provided by Sunsolve. The proposed structure geometry slightly improved the SHJ cell optical current density by ~0.37% (rel.), and hence efficiency (η) by about 0.4% (rel.). The SHJ cell efficiency improved by 21.68% after applying thinner back ITO of about 30 nm overlayed on ~1 nm MoS2. The efficiency improvement following the application of MoS2 is tentatively attributed to the increased NIR absorption in the silicon bulk due to the light constructive interface with the backside components, namely silver (Ag) and ITO. Study outcomes showed that improved SHJ efficiency could be further optimized by addressing front cell components, mainly front ITO and MoS2 contact engineering.

Passivating Lead Halide Perovskites Using Pyridinium Salts with Superhalogen Atoms

Passivating lead halide perovskites using pyridinium salts has attracted enormous attention, but the excellent surface passivation of the halide perovskites has not been achieved by using only a pyridinium salt until now. Herein, passivating the (001) planes of the cubic CsPbI3, CH3NH3PbI3, and NH2CHNH2PbI3 perovskites using the pyridinium salts of C5NH6X (X = Cl, Br, I, PF6, ClO4, or BF4) is systematically studied by high-throughput first-principle calculations and ab initio molecular dynamics simulations. The results show that the excellent surface passivation of the three perovskites is achieved by the pyridinium salt of C5NH6BF4 (i.e., shallow level, negative formation energy, unchanged band-edge construction, and stable dynamics property are obtained for the three passivated perovskites), which strongly imply that their devices can show excellent performances, such as long-term stability, low ion migration, and high efficiency. However, the C5NH6ClO4 and C5NH6PF6 pyridinium salts are only profitable for passivating the (001) PbI2 plane of the three perovskites, and other C5NH6X pyridinium salts have adverse effects.

Industrial metallization of fired passivating contacts for n-type tunnel oxide passivated contact (n-TOPCon) solar cells

Poly-Si/SiO x passivating contacts enable the manufacturing of highly-efficient Si solar cells, but their fabrication commonly relies on an extra high-temperature process such as dopant diffusion or thermal annealing for achieving excellent passivation and contacting properties. This extra process is eliminated in the fired passivating contact (FPC) approach used for simplified fabrication of poly-Si/SiO x passivating contacts. Instead, FPCs rely on the thermal budget of the fast/short and high-temperature firing process used for metallization of solar cells to achieve similar final properties. Despite this, compatibility of FPCs with industrially viable metallization techniques has not been demonstrated yet, which is studied in this work for fire-through Ag screen-printing and Ni/Ag plating. With screen-printing, low recombination current density ( J 0 ) down to 4.9 fA/cm 2 , low contact resistivity between the Ag contacts and the FPC ( ρ c,m ) down to 7.2 mΩ⋅cm 2 , and Ohmic transport through the FPC including the SiO x film were achieved using wet-chemically grown SiO x . Nevertheless, J 0 of metallized regions ( J 0,m ) exceeded 1000 fA/cm 2 . Reducing J 0,m was attempted by mitigating the blistering observed in FPCs, but J 0,m remained high. With Ni/Ag plating, excellent surface passivation with J 0 down to 2.7 fA/cm 2 and very low J 0,m < 50 fA/cm 2 were achieved, but no Ohmic contacts could be obtained. Integration of screen-printed FPCs in large-area n-TOPCon solar cells was also demonstrated, yielding average efficiencies of 18.4%, limited mainly by the high J 0,m and series resistance of the FPCs. The results presented reveal the challenges for the industrialization of FPCs and provide valuable insights for tackling these. • Fired passivating contacts (FPCs) developed relying only on the thermal budget of firing and not on conventional annealing. • Compatibility of FPCs with fire-through Ag screen-printing and Ni/Ag plating tested. • Screen-printing: J 0,pass ≈ 5 fA/cm 2 & ρ c < 10 mΩ∙cm 2 achieved, but J 0,metal was high. • Plating: J 0,pass < 3 fA/cm 2 & J 0,metal < 50 fA/cm 2 achieved, but contacts were non-Ohmic. • Integration of FPCs in screen-printed large-area n-TOPCon cells led to 18.4% efficiency.

Interdigitated back-contacted crystalline silicon solar cells fully manufactured with atomic layer deposited selective contacts

The interdigitated back-contacted (IBC) solar cell concept has been extensively studied for single-junction cells and more recently as a good choice for three-terminal tandem devices. In this work, carrier-selective contacts based on transition metal oxides deposited by atomic layer deposition (ALD) technique are applied to IBC c-Si(n) devices. In the first part of the study, we develop a hole-selective contact based on thin ALD vanadium oxide (V2O5) layers without using an amorphous silicon interlayer. The ALD process has been optimised, i.e. number of ALD cycles and deposition temperature, as a trade-off between surface passivation and contact resistivity. Noticeable surface passivation with recombination current densities around 100 fA/cm2, as well as reasonable contact resistivity values below 250 mΩcm2 are reached using 200 ALD V2O5 cycles deposited at a deposition temperature of 125 °C (∼10 nm layer thickness). The optimised ALD V2O5-based contact is combined with both an ALD TiO2-based electron-selective contact and an excellent surface passivation in non-contacted regions provided by ALD Al2O3 films, to form a fully ALD IBC c-Si(n) solar cell scheme. Fabricated devices yield photovoltaic efficiencies and pseudo efficiencies, i.e. calculated without series resistance losses, of 18.6% and 21.1% respectively (3 cm × 3 cm device area). These results reveal the potential of the ALD technique to deposit transition metal oxide (TMO) films as selective contacts on high efficiency devices, paving the way of using low thermal-budget, low cost and highly scalable processes for a highly demanding IBC solar cell architecture in the photovoltaic industry.

Impurity Gettering in Polycrystalline‐Silicon Based Passivating Contacts—The Role of Oxide Stoichiometry and Pinholes

AbstractPolycrystalline‐silicon/oxide (poly‐Si/SiOx) passivating contacts for high efficiency solar cells exhibit excellent surface passivation, carrier selectivity, and impurity gettering effects. However, the ultrathin SiOx interlayer can act as a diffusion barrier for metal impurities and this potentially slows down the overall gettering rate of the poly‐Si/SiOx structures. Herein, the factors that determine the blocking effects of the SiOx interlayers are identified and investigated by examining two general types of the SiOx interlayers: 1.3 nm ultrathin tunneling SiOx with negligible pinholes and 2.5 nm SiOx with thermally created pinholes. Iron is used as tracer impurity in silicon to quantify the gettering rate. By fitting the experimental gettering kinetics by a diffusion‐limited segregation gettering model, the blocking effects of the SiOx interlayers are quantified by a transport parameter. Both the oxide stoichiometry and pinhole density affect the effective transport of iron through SiOx interlayers. The oxide stoichiometry depends strongly on the oxidation method, while the pinhole density is affected by the activation temperature, doping concentration, doping technique, and possibly the dopant type as well. To enable a fast gettering process during typical high‐temperature formation of the poly‐Si/SiOx structures, a SiOx interlayer that is less stoichiometric or with a higher pinhole density is preferred.

Intrinsic layer modification in silicon heterojunctions: Balancing transport and surface passivation

In this work, the intrinsic hydrogenated amorphous silicon (a-Si:H) layer of silicon heterojunction (SHJ) solar cells was modified to improve carrier transport while maintaining excellent passivation of the c-Si absorber surface. The microstructure of different multilayer intrinsic a-Si:H films was measured and its influence on contact resistance and passivation quality was investigated thoroughly. We show that a pronounced trade-off between passivation and transport exists and that this trade-off is governed by the a-Si:H properties close to the c-Si surface. The fact that the same trend was observed for hole and electron contact suggests that the transport barrier formed by the interfacial a-Si:H layer is governed by a higher resistivity of the void-rich interfacial layer or a less pronounced induced junction and not by asymmetric hole or electron barriers (band offsets, tunnel efficiencies, …). Modified intrinsic layers have been tested on cell level, resulting in a series resistance ( R s ) reduction by about 0.3 Ωcm 2 and an increase in fill factor ( FF ) by roughly 1.0 % abs . The power conversion efficiency ( η ) was improved by about 0.3 % abs with respect to our baseline. Further, the beneficial effect of a hydrogen plasma treatment (HPT) on passivation and transport of the hole contact was shown on device level. • Void-rich a-Si(i) is essential to prevent epitaxial growth for good surface passivation, but is also the main contributor to a-Si:H(i)-induced transport losses for both electron and hole contact. • Both thickness and microstructure of the void-rich a-Si:H(i) are decisive for the cell’s series resistance, small differences can have a huge impact on transport and surface passivation. • The microstructure of void-rich a-Si:H(i) is carefully tailored towards denser films via a-Si:H deposition parameters and a post-deposition hydrogen plasma treatment to significantly improve transport and the conversion efficiency of SHJ solar cells.

Approaching 23% efficient n-type crystalline silicon solar cells with a silicon oxide-based highly transparent passivating contact

The concept of passivating contacts is indispensable for realizing high-efficiency crystalline silicon (c-Si)-based solar cells, and its implementation and integration into production lines has become an essential research subject. A desirable transparent passivating contact should theoretically combine excellent electrical conductivity, distinguished surface passivation and high optical transparency. However, it is challenging to simultaneously achieve the optimization of all three requirements. Here, the application potential of the phosphorous-doped polycrystalline silicon-oxide (n-poly-SiOx) as an efficient hole-selective contact in tunnel oxide passivated contact (TOPCon) solar cells is highlighted. The oxygen content can be regulated by the carbon dioxide (CO2) gas flow during the plasma enhanced chemical vapor deposition (PECVD) process, and the optimal doping concentration is determined. While the wide band gap of n-poly-SiOx enables ideal optical performance, it also ensures excellent passivation and high conductivity, which eventually translates into an optimized short-circuit current density (41.53 mA/cm2), fill factor (79.21%), open-circuit voltage (687.8 mV) and efficiency of 22.62% for the proof-of-concept TOPCon solar cell. Additionally, this contact with the incorporation of oxygen elements can suppress the formation of hydrogen-induced blisters, which critically degrades passivation. Our work highlights a promising strategy to improve the performance of TOPCon solar cells by employing n-poly-SiOx based transparent passivating contact, and its passivation mechanism and working principle are also investigated.

Activation and Deactivation of Silicon Surface Passivation by Niobium Oxide Films

Niobium oxide (Nb2O5) films can provide excellent passivation for crystalline silicon (c‐Si) surface after postdeposition annealing, however, its kinetic behavior and mechanism have not been explored. Herein, it is demonstrated that surface passivation by solution‐processed Nb2O5 films can be activated by low‐temperature annealing (&lt;200 °C) within several minutes, with the activation energy of 0.40 and 0.57 eV for hydrofluoric acid (HF) and RCA pretreated surfaces, respectively. Moreover, passivation is deactivated by higher‐temperature annealing (&gt;350 °C), with the deactivation energy of 0.86 and 1.06 eV for HF and RCA pretreated surfaces, respectively. The results combined with surface‐sensitive X‐Ray photoelectron spectroscopy (XPS) measurements indicate that the passivation kinetics of Nb2O5 on the surface of c‐Si are strongly related to the diffusion of hydrogen into and out of the Nb2O5/c‐Si interface.

Zn1-xGexOy Passivating Interlayers for BaSi2 Thin-Film Solar Cells.

BaSi2 is a promising absorber material for next-generation thin-film solar cells (TFSCs). For high-efficiency TFSCs, a suitable interlayer should be found for every light absorber. However, such an interlayer has not been studied for BaSi2. In this study, we investigated amorphous Zn1-xGexOy films as interlayers for BaSi2. The Zn/Ge atomic ratio in the Zn1-xGexOy film and the optical band gap depend on the substrate temperature during sputtering deposition. A suitable i-Zn1-xGexOy/BaSi2 heterointerface with spike-type conduction band offset was achieved when Zn1-xGexOy was deposited on BaSi2 at 50 °C. Furthermore, photoresponsivity measurements revealed that Zn1-xGexOy has an excellent surface passivation effect on BaSi2. When the thickness of Zn1-xGexOy was 2 nm, a high photoresponsivity of 0.9 A/W was obtained for a 500 nm thick BaSi2 layer at a wavelength of 780 nm under an applied bias voltage of 0.5 V between the front and rear electrodes, where the photoresponsivity in the short-wavelength region was significantly improved compared with that of BaSi2 capped with an amorphous Si layer. X-ray photoelectron spectroscopy revealed that the Zn1-xGexOy films suppressed the oxidation of the BaSi2 surface, decreasing the carrier recombination rate. This is the first demonstration of passivation interlayers for BaSi2 with suitable band alignment for carrier transport and surface passivation effects.

Plasma‐Induced Nanocrystalline Domain Engineering and Surface Passivation in Mesoporous Chalcogenide Semiconductor Thin Films

AbstractThe synthesis of highly crystalline mesoporous materials is key to realizing high‐performance chemical and biological sensors and optoelectronics. However, minimizing surface oxidation and enhancing the domain size without affecting the porous nanoarchitecture are daunting challenges. Herein, we report a hybrid technique that combines bottom‐up electrochemical growth with top‐down plasma treatment to produce mesoporous semiconductors with large crystalline domain sizes and excellent surface passivation. By passivating unsaturated bonds without incorporating any chemical or physical layers, these films show better stability and enhancement in the optoelectronic properties of mesoporous copper telluride (CuTe) with different pore diameters. These results provide exciting opportunities for the development of long‐term, stable, and high‐performance mesoporous semiconductor materials for future technologies.

Plasma-Induced Nanocrystalline Domain Engineering and Surface Passivation in Mesoporous Chalcogenide Semiconductor Thin Films.

The synthesis of highly crystalline mesoporous materials is key to realizing high‐performance chemical and biological sensors and optoelectronics. However, minimizing surface oxidation and enhancing the domain size without affecting the porous nanoarchitecture are daunting challenges. Herein, we report a hybrid technique that combines bottom‐up electrochemical growth with top‐down plasma treatment to produce mesoporous semiconductors with large crystalline domain sizes and excellent surface passivation. By passivating unsaturated bonds without incorporating any chemical or physical layers, these films show better stability and enhancement in the optoelectronic properties of mesoporous copper telluride (CuTe) with different pore diameters. These results provide exciting opportunities for the development of long‐term, stable, and high‐performance mesoporous semiconductor materials for future technologies.

Multifunctional Heterocyclic-Based Spacer Cation for Efficient and Stable 2D/3D Perovskite Solar Cells.

Two-dimensional/three-dimensional (2D/3D) Ruddlesden-Popper perovskite materials have shown the enormous potential to achieve both efficient and stable photovoltaic devices for commercial applications. Unfortunately, the single function of spacer cations limits their further improvements in efficiency to reach values as high as those of 3D perovskites. Herein, we developed a new-type multifunctional heterocyclic-based spacer cation of 2-(methylthio)-4,5-dihydro-1H-imidazole (MTIm+) to achieve a synchronous improvement of efficiency and stability for 2D/3D perovskite solar cells (PSCs). Owing to the presence of special chemical groups (imidazole and methylthio), strong interactions have been found between MTIm+ and the 3D perovskite component, leading to an excellent passivation effect. More important, at the initial stage of crystallization, uniform nucleation distribution would be generated around the spacer cation, which is helpful for improved crystallinity and reduced growth defects. The smaller layer space compared to that of cations based on aromatic hydrocarbons caused effective carrier transfer between inorganic layers in 2D/3D perovskites. As a result, the 2D/3D (n = 30) PSCs based on MTIm exhibit a champion PCE up to 21.25% with a high Voc of 1.14 V. Besides, the 2D/3D perovskite devices have realized dramatically enhanced humidity and thermal stability, maintaining 94% of the starting PCE enduring aging at about 50% RH for 2880 h and at 85 °C for 360 h, respectively. We believe that it would provide a significant strategy to further promote the photovoltaic performances and the long-term stability of 2D/3D perovskite devices toward future practical applications.

Research on optimization of annealing process based on N-type TOPCon solar cell

In recent years, developing new structure and technology has always been an important link in the production and manufacture on photovoltaic cells. Among all high-efficiency crystalline silicon solar cells, the tunnel oxide passivated contact (TOPCon) solar cell has attracted much attention due to its excellent passivation and compatibility with the traditional crystalline silicon solar cells. This article first introduces the basic structure and process route of the tunneling oxide passivation contact (TOPCon) solar cell. Then the annealing process was studied. Experiments on the effects of different annealing temperatures and times on the doping characteristics were carried out, and the experimental results were analyzed. The experimental results show that the annealing temperature and time have a very important effect on the annealing effect of ion implanted silicon. Finally, the light injection annealing process is researched and experimented. Experimental results show that the efficiency of the light injection annealing method is significantly improved, which is mainly manifested in the improvement of Voc (open circuit voltage) and FF (fill factor).