| In the third decade of the 21st century,China announced to the world the important national goal of carbon peaking and carbon neutrality during the 14th Five-Year Plan period,which took the key step for the energy revolution and the low-carbon energy transition.Herein,it becomes essential influences that innovating lighting technology and exploring photoluminescence(PL)materials.Halide perovskites have been one of the widely-studied photoelectric functional materials,due to the simple synthesis,low-cost material,multifunctional carrier,tunable PL and high efficiency.In our study,we state the halide perovskites with kinds of sizes,morphologies and configuration within charge-carrier dynamics on the basis of their dimensional structures and optical applications.Furthermore,we improved the stability and efficiency via tructural modification and tunable photogenerated carrier process.Specifically,the main research results of this dissertation are as follows:1.A series of three-dimensional CsPbI3@xH2TPP nanocrystals were synthesized by modified hot injection method introducing tetraphenylporphyrin(H2TPP)as conjugated organic small molecule ligand into precursor.Controlling the content of H2TPP in the nanocrystals is an effective approach to optimize the stability and quality,broaden the absorption in the spectral range,improve PL at different excitation wavelengths,further achieve efficient and stable red emission.Through ultrafast transient absorption spectroscopy and other advanced characterization,we investigated the carrier dynamics and highlighted the following main points:(1)The introduction of H2TPP in nanocrystals contribute to surface defect passivation to construct more stable structure.(2)Beside that,it also contribute to charge transfer process from donor to accepter to achieve high-efficiency PL at different excitation wavelengths.(3)CsPbI3@xH2TPP nanocrystals would exhibit more excellent optical potential while x=2.5%.2.A series of three-dimensional Cs2AgIn1-γ-xBixLaγCl6 nanocrystals were synthesized by hot injection method introducing the activator ions La3+or Bi3+into the lattice of Cs2AgInCl6.Controlling the proportion of La3+or Bi3+in the nanocrystals is an effective approach to optimize the stability and quality,break the parity-forbidden transition,create new optical absorption channel,further achieve bright broadband warm-white emission in the visible light region.Through ultrafast transient absorption spectroscopy and other advanced characterization,we investigated the carrier dynamics and highlighted the following main points:(1)The high-efficiency PL is induced by triplet self-trapping exciton emission.(2)Substituting In3+ to the activator ions La3+-Bi3+ facilitated the singlet-triplet transition by lengthening the lifetime and quickening the intersystem crossing process.(3)Cs2AgIn1-γ-xBixLaγCl6 nanocrystals would exhibit more excellent optical potential while x=0.15 and γ=0.25.3.A series of vacancy-ordered Cs2PtxSn1-xCl6 solid solutions were synthesized by hydrothermal method introducing the activator ions Pt4+ into the lattice of Cs2SnCl6.Controlling the proportion of Sn4+or Pt4+ in the solid solutions is a feasible approach to optimize the air-stability,water-stability and photo-stability,tune the optical band gap,create new optical absorption channel,further achieve switchable photoluminescence and photocatalytic hydrogen evolution activity in water.Through various techniques of optical spectroscopy,photoelectrochemistry and photocatalysis,we investigated the carrier dynamics and highlighted the following main points:(1)There are tunable functional radiative recombination and non-radiative recombination process in the Cs2PtxSn1-xCl6 solid solutions.(2)The carrier recombination process depends on the existence state of sub-bandgap states.(3)As high content of Pt substitution,the photoluminescence function of Cs2PtxSn1-xCl6(x=0.75)is activated.On the contrary,the photocatalytic function of Cs2PtxSn1-xCl6(x=0.05)is activated. |
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