Nd:NaBi(WO_4)_2 crystals (Nd:NBW) were grown by Czochralski method. The pulling rate is 0.3 mm·h (-1),and the rotational speed of Nd:NBW crystal is 2 r·min (-1). The components of this single crystal were de...Nd:NaBi(WO_4)_2 crystals (Nd:NBW) were grown by Czochralski method. The pulling rate is 0.3 mm·h (-1),and the rotational speed of Nd:NBW crystal is 2 r·min (-1). The components of this single crystal were determined by X-ray diffractions,and its corresponding properties were described from thermal gravity and differential thermal analysis experiments. The absorption cross-sections were calculated. The emission band of Nd:NBW crystal was obtained from its luminous spectrum.展开更多
Kesterite Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)has attracted considerable attention as a non-toxic and earthabundant solar cell material.During selenization of CZTSSe film at high temperature,the reaction between CZTSSe and Mo...Kesterite Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)has attracted considerable attention as a non-toxic and earthabundant solar cell material.During selenization of CZTSSe film at high temperature,the reaction between CZTSSe and Mo is one of the main reasons that result in unfavorable absorber and interface quality,which leads to large open circuit voltage deficit(VOC-def)and low fill factor(FF).Herein,a WO_(3)intermediate layer introduced at the back interface can effectually inhibit the unfavorable interface reaction between absorber and back electrode in the preliminary selenization progress;thus high-quality crystals are obtained.Through this back interface engineering,the traditional problems of phase segregation,voids in the absorber and over thick Mo(S,Se)_(2)at the back interface can be well solved,which greatly lessens the recombination in the bulk and at the interface.The increased minority carrier diffusion length,decreased barrier height at back interface contact and reduced deep acceptor defects give rise to systematic improvement in VOCand FF,finally a 12.66%conversion efficiency for CZTSSe solar cell has been achieved.This work provides a simple way to fabricate highly efficient solar cells and promotes a deeper understanding of the function of intermediate layer at back interface in kesterite-based solar cells.展开更多
Luminescence ratiometric thermometry based on rare earth(RE)ions has attracted great interest for the potential applications in many fields.But the improvement of the measurement sensitivity and accuracy is significan...Luminescence ratiometric thermometry based on rare earth(RE)ions has attracted great interest for the potential applications in many fields.But the improvement of the measurement sensitivity and accuracy is significantly restricted due to the small energy gap between thermally coupled levels(TCL).Here,a strategy striving for good thermometric properties of luminescent materials was designed by using the phosphors mixture composed of NaY(WO_(4))_(2):Nd^(3+)-Yb^(3+)and NaY(WO_(4))_(2):Er^(3+),which were prepared by secondary sintering method.Under the excitation of 980 nm lase r,the near-infrared(NIR)emissions(710-920 nm)from Nd^(3+)ions are effectively strengthened when the temperature increases from 304 to773 K,whereas Er^(3+)NIR luminescence centered at around 1536 nm is thermally quenched.The remarkably different response of NIR emissions to the thermal variation allows us to map temperature through the ratiometric method.By optimizing the dopant concentration of rare earth(RE)ions,a maximum sensitivity of 5.14%/K together with a measurement uncertainty of about 0.1 K is acquired at304 K,which is superior to the previously reported RE luminescence-based temperature sensors,indicating that the approach developed here can pave the way for achieving optical thermometry with desired properties.展开更多
文摘Nd:NaBi(WO_4)_2 crystals (Nd:NBW) were grown by Czochralski method. The pulling rate is 0.3 mm·h (-1),and the rotational speed of Nd:NBW crystal is 2 r·min (-1). The components of this single crystal were determined by X-ray diffractions,and its corresponding properties were described from thermal gravity and differential thermal analysis experiments. The absorption cross-sections were calculated. The emission band of Nd:NBW crystal was obtained from its luminous spectrum.
基金supported by the National Key R&D Program of China(no.2018YFE0203400)the National Natural Science Foundation of China(no.62074102)+1 种基金the Guangdong Basic and Applied Basic Research Foundation(no.2022A1515010979)the Science and Technology plan project of Shenzhen(nos.JCYJ20190808120001755 and 20220808165025003)。
文摘Kesterite Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)has attracted considerable attention as a non-toxic and earthabundant solar cell material.During selenization of CZTSSe film at high temperature,the reaction between CZTSSe and Mo is one of the main reasons that result in unfavorable absorber and interface quality,which leads to large open circuit voltage deficit(VOC-def)and low fill factor(FF).Herein,a WO_(3)intermediate layer introduced at the back interface can effectually inhibit the unfavorable interface reaction between absorber and back electrode in the preliminary selenization progress;thus high-quality crystals are obtained.Through this back interface engineering,the traditional problems of phase segregation,voids in the absorber and over thick Mo(S,Se)_(2)at the back interface can be well solved,which greatly lessens the recombination in the bulk and at the interface.The increased minority carrier diffusion length,decreased barrier height at back interface contact and reduced deep acceptor defects give rise to systematic improvement in VOCand FF,finally a 12.66%conversion efficiency for CZTSSe solar cell has been achieved.This work provides a simple way to fabricate highly efficient solar cells and promotes a deeper understanding of the function of intermediate layer at back interface in kesterite-based solar cells.
基金Project supported by the National Natural Science Foundation of China(61505174)。
文摘Luminescence ratiometric thermometry based on rare earth(RE)ions has attracted great interest for the potential applications in many fields.But the improvement of the measurement sensitivity and accuracy is significantly restricted due to the small energy gap between thermally coupled levels(TCL).Here,a strategy striving for good thermometric properties of luminescent materials was designed by using the phosphors mixture composed of NaY(WO_(4))_(2):Nd^(3+)-Yb^(3+)and NaY(WO_(4))_(2):Er^(3+),which were prepared by secondary sintering method.Under the excitation of 980 nm lase r,the near-infrared(NIR)emissions(710-920 nm)from Nd^(3+)ions are effectively strengthened when the temperature increases from 304 to773 K,whereas Er^(3+)NIR luminescence centered at around 1536 nm is thermally quenched.The remarkably different response of NIR emissions to the thermal variation allows us to map temperature through the ratiometric method.By optimizing the dopant concentration of rare earth(RE)ions,a maximum sensitivity of 5.14%/K together with a measurement uncertainty of about 0.1 K is acquired at304 K,which is superior to the previously reported RE luminescence-based temperature sensors,indicating that the approach developed here can pave the way for achieving optical thermometry with desired properties.
