[LIU, Guiwu 刘桂武, LIU, Junlin 刘军林, ZHU, Yuan 祝园, QIAO, Guanjun 乔冠军, ZHANG, Xiangzhao 张相召, LV, Quanjiang 吕全江, HOU, Haigang 侯海港, YANG, Jian 杨建] No.301, Xuefu Road, Jingkou District 中国江苏省镇江市京口区学府路301号, Jiangsu 212013Zhenjiang, Jiangsu 212013 A photoelectric thin film and a preparation method therefor, especially a layered polycrystalline lead selenide thin film and a preparation method therefor. The preparation method mainly comprises: (1) preparing a dense lead selenide layer on a substrate (2) by using a chemical bath method; (2) preparing a loose oxygen-containing basic lead carbonate layer on the dense lead selenide layer by using the chemical bath method; and (3) placing a sample attached with the dense lead selenide layer and the oxygen-containing basic lead carbonate layer in a selenium ion-containing solution for an ion exchange reaction so as to finally form a layered polycrystalline lead selenide thin film. The preparation method is simple and convenient in process, low in cost and good in controllability. The prepared lead selenide thin film consists of a lower dense polycrystalline cubic lead selenide layer and an upper loose polycrystalline cubic lead selenide layer, and can be widely applied to the manufacturing of components in the field of photoelectric conversion or thermoelectric conversion, such as infrared sensors, solar cells, laser emitters, and thermoelectric converters.

[LIU, Junlin 刘军林, LV, Quanjiang 吕全江, HOU, Haigang 侯海港, LIU, Guiwu 刘桂武, QIAO, Guanjun 乔冠军, HAO, Juncao 郝俊操, XIA, Songmin 夏松敏, CHEN, Jie 陈杰] {Room 214, Building 23, North Central Area, Suzhou Nanotown 中国江苏省苏州市中国（江苏）自由贸易试验区苏州片区苏州金鸡湖大道99号苏州纳米城中北区23幢214室, Jiangsu 215002No.99, Jinjihu Avenue, Suzhou Area, China (Jiangsu) Pilot Free Trade ZoneSuzhou, Jiangsu 215002;CN CN(CN)(CN)} The present invention belongs to the technical field of photoelectricity. Disclosed is a MEMS infrared light source with improved photoelectric conversion efficiency. The light source comprises a substrate (101), a support layer (501), a heating electrode layer (601), an infrared emission layer (901) and two heating electrode pads (801) electrically connected to the heating electrode layer (601), which are sequentially stacked from bottom to top. An upper surface of the substrate (101) is provided with a pit (100) recessed downwards, and the pit (100) comprises a horizontal bottom surface and a slope-like side wall. The substrate (101), which is a four-sided fixed support structure, is connected to the support layer (501), which is above same, and a cavity structure is formed between the substrate and the support layer. An enclosed area of an upper opening of the pit (100) is located at inner sides of the two heating electrode pads (801), and a distribution area in an extension direction of the heating electrode pads (801) is beyond the range of the heating electrode pads (801). At least one penetrating sacrificial window (1002) is arranged in the support layer (501). Complete reflective layers (301) are arranged on a bottom surface and a side wall of the pit (100). The MEMS infrared light source with improved photoelectric conversion efficiency solves the problems of increased heat capacity, poor stress resistance, relatively poor durability, etc., of a device possibly due to the structural design of a substrate and a reflective layer in an existing MEMS infrared light source. The present invention belongs to the technical field of photoelectricity. Disclosed is a MEMS infrared light source with improved photoelectric conversion efficiency. The light source comprises a substrate (101), a support layer (501), a heating electrode layer (601), an infrared emission layer (901) and two heating electrode pads (801) electrically connected to the heating electrode layer (601), which are sequentially stacked from bottom to top. An upper surface of the substrate (101) is provided with a pit (100) recessed downwards, and the pit (100) comprises a horizontal bottom surface and a slope-like side wall. The substrate (101), which is a four-sided fixed support structure, is connected to the support layer (501), which is above same, and a cavity structure is formed between the substrate and the support layer. An enclosed area of an upper opening of the pit (100) is located at inner sides of the two heating electrode pads (801), and a distribution area in an extension direction of the heating electrode pads (801) is beyond the range of the heating electrode pads (801). At least one penetrating sacrificial window (1002) is arranged in the support layer (501). Complete reflective layers (301) are arranged on a bottom surface and a side wall of the pit (100). The MEMS infrared light source with improved photoelectric conversion efficiency solves the problems of increased heat capacity, poor stress resistance, relatively poor durability, etc., of a device possibly due to the structural design of a substrate and a reflective layer in an existing MEMS infrared light source.