隨著非破壞性檢測與低劑量醫學影像需求的日益增加，開發兼具高靈敏度與極低偵測極限的先進X光感測器成為當前光電領域的重要課題。雖然金屬鹵化物鈣鈦礦因具備極高的X光吸收截面與優異的載子傳輸特性而備受矚目，但傳統高效能材料多高度依賴重金屬鉛(Pb)，伴隨而來的環境污染與人體毒性疑慮，成為其邁向商業化的最大阻礙。此外，現有研究多仰賴耗時且難以大面積量產的單晶生長技術，進一步限縮了其實際應用的可行性。在眾多無鉛替代方案中，屬於226結構型態(A2B’B’’X6)的雙鈣鈦礦因具備高度對稱的三維晶體框架，展現出卓越的熱力學與環境穩定性，能有效抵抗高能輻射照射所引起的材料裂解。在元素配置上，此實驗選用鉍(Bi)的原子序高達83，無毒且與鉛(Pb)具備相似的孤電子對效應，能為材料提供極佳的X光吸收截面與光子衰減能力(Stopping power)，在226鈣鈦礦的研究體系中，Cs2AgBiBr6在X光感測器已經獲得還不錯成果，但相較於地球含量豐富且低成本的銅(Cu)離子，(Cu-Bi)體系所做的研究還較少，本研究創新導入全無機無鉛雙鈣鈦礦Cs2CuBiBr6作為X光感測元件之核心吸收層，采用在大氣中手動噴塗法來製作大面積厚膜元件，成功於基板上沉積出緻密且具備規模化潛力的Cs2CuBiBr6厚膜，并對材料的基本特性分析進行研究，後續討論不同基板溫度和退火溫度條件下的生長機制，通過溫度調控生長出更大顆緻密的晶粒，讓載子傳輸更好，更緻密的堆積使得膜層中的缺陷更少，獲得了更低的暗電流表現，還證實了Cs₂CuBiBr₆雙鈣鈦礦材料之厚膜在大氣中具有優異的總體晶格結構穩定性和宏觀化學穩定性；儘管元件目前並未表現出X光電流響應，但後續如果使用機器噴塗設備更精準地調控工藝參數，進而生長出更加均勻、微觀缺陷更少且厚度更厚之高品質膜層，在未來發展成為更廉價的新一代X光探測器還是極具潛力的。

With the increasing demand for non-destructive testing and low-dose medical imaging, developing advanced X-ray sensors with high sensitivity and an extremely low limit of detection has become a crucial issue in optoelectronics. Although metal halide perovskites possess excellent X-ray absorption and carrier transport properties, their reliance on toxic heavy metal lead (Pb) and difficult-to-scale single-crystal growth techniques hinder their commercialization. Among lead-free alternatives, A₂B'B''X₆ double perovskites exhibit outstanding thermodynamic and environmental stability against high-energy radiation. Specifically, non-toxic bismuth (Bi) offers a high atomic number and a lone-pair electron effect similar to lead, providing excellent photon stopping power, yet the earth-abundant and low-cost (Cu-Bi) system remains relatively underexplored compared to its silver-based counterparts. To address this, this study innovatively introduces the all-inorganic lead-free double perovskite Cs₂CuBiBr₆ as the core absorbing layer for X-ray sensors. Using a manual spray-coating method in an ambient atmosphere, we successfully deposited dense, scalable Cs₂CuBiBr₆ thick films. Fundamental characterizations and analyses of growth mechanisms under various substrate and annealing temperatures revealed that optimized temperature regulation promotes larger, denser grains and improved carrier transport. This denser packing significantly reduces film defects, resulting in a lower dark current while demonstrating excellent overall lattice and macroscopic chemical stability in ambient conditions. Although the current device has not yet exhibited an X-ray photocurrent response, it holds significant potential for development into a cost-effective, next-generation X-ray detector by implementing automated machine spray-coating equipment to precisely control process parameters and grow more uniform, thicker, and higher-quality films with fewer microscopic defects.

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