آصف علی
افسوس ہے کہ اس مہینہ کے شروع میں ہماری قومی و ملی جماعت کی دو ممتاز شخصیتیں ہم سے جدا ہوگئیں یعنی آصف علی مرحوم اور شفیق الرحمن مرحوم قدوائی نے انتقال کیا، یہ دونوں پرانے قومی کا رکن تھے، ملک و وطن کی انھوں نے بڑی خدمات انجام دیں اور اس کے لئے قید و بند کی مصیبتیں جھیلیں، ہندوستان کی آزادی کی جدوجہد میں ان کا نمایاں حصہ تھا، آصف علی صاحب مرحوم تو پرانے آدمی اور مشہور و ممتاز شخصیت رکھتے تھے، سیاسی ز ندگی سے پہلے بھی وہ ایک اچھے بیرسٹر تھے، اور سیاست کے میدان میں بھی ان کو نمایاں مقام حاصل تھا، اور ہندوستان کے بڑے لیڈروں میں ان کا شمار تھا، ہندوستان کی آزادی کے بعد وہ مرکزی حکومت کی وزارت، اڑیسہ کی گورنری، امریکہ اور سوئیزرلینڈ کی سفارت جیسے بڑے بڑے عہدوں پر ممتاز رہے، اور سو ئیزرلینڈ میں ہی ان کا انتقال ہوا، علمی حیثیت سے بھی وہ بڑے لائق اور ذہین وذکی تھے، اردو کے بھی ادیب تھے اور انگریزی و اردو دونوں میں ان کی تصانیف ہیں، انتقال کے وقت ۶۴، ۶۵ سال کی عمر تھی، ان کی موت سے ایک ایسی جگہ خالی ہوگئی جس کا موجودہ حالات میں پر ہونا مشکل ہے۔ (شاہ معین الدین ندوی، اپریل ۱۹۵۳ء)
This study deals with a historical overview of the entry of Islam to the Indian subcontinent and the contribution of the companions, successor, and their followers in spreading the Prophetic Sunnah in it. Moreover, It contains a brief historical overview of the emergence of hadīth science، its weakness, renaissance, development, and flourishing, and a study of the attention of Muhaddithūn to the Sahih al-Bukhārī by writing its Shuruh, Taliqāt، Hawāshī, and Tarājim in the Indian subcontinent. It has been proven from the study of the history of hadīth science that after the entry of the Ghaznavids and the Ghurids to this region, the science of hadīth weakened due to the interest of the locals in rational sciences until Sultān Ala’ud-Dīn al-Khiljī (d. 716/1316) period. The scholars began to pay attention to the compilations of hadīth in general and Sahih al-Bukhārī in particular, and the first Sharh of Sahih al-Bukhārī appeared by Sheikh al-Hassan b. Muhammad al-Saghānī al-Lāhourī (d. 1252/650). It was revealed from a historical study of Sahih al-Bukhārī’s related studies in the Indian subcontinent that all were written in three stages. The first stage was the era of the renaissance of hadīth science and the emergence of Sahih al-Bukhari’s Shuruh and Hawāshī in the Arabic language. The second stage was the era of the development of hadīth sciences and the emergence of Sahih al-Bukhari’s Shuruh and Tarājim in the Arabic and Persian languages. Besides, the study proved that it was the era of translation and authorship in the Persian language, which was one of the most widespread languages، understanding, and delivered in the scientific community of the Indian subcontinent. As for the third stage, it is the flourishing of hadīth science and the emergence of a diversity of books about the Sahih al-Bukhārī in Arabic, Urdu, and Pashto. It was discovered from the study that the Urdu language took the place of Persian in the dissemination of legal sciences and the authorship of Sahih al-Bukhārī.
The hybrid perovskite solar cells have become a key player in third generation photovoltaics since the first solid state perovskite photovoltaic cell was reported in 2012. Over the course of this work, a wide array of subjects has been treated: starting with the synthesis and deposition of different charge transport layers, synt hesis of hybrid perovskite materials, optimization of annealing temperature, stability of the material with the addition of inorganic metal ions, and photovoltaic device fabrications. The key advantages of methylammonium lead iodide (CH3NH3PbI3=MAPbI3; CH3NH3=MA) perovskite is the efficient absorption of light, optimum band gap and long carrier life time. The organic components, i.e. CH3NH3, in MAPbI3 perovskites bring instabilities even at ambient conditions. To address such instabilities, an attempt has been made to replace the organic constituent with inorganic monovalent cations; K+1, Rb+1, and Cs+1 in MAPbI3; (MA)1-xBxPbI3 (B= K, Rb, Cs; x=0-1). The optical, morphological, structural, chemical, optoelectronic and electrical properties of the materials have been explored by employing different characterization techniques. Initially methylammonium lead iodide (MAPbI3) compound grows in a tetragonal crystal structure, which remains intact with lower doping concentrations. However, the crystal structure of the material is found to be transformed from tetragonal at lower doping to double phase i.e., simultaneous existence of tetragonal MAPbI3 and orthorhombic BPbI3 (B=K, Rb, Cs) structure at higher doping concentrations. These structural phase transformations are also visible in electron micrographs of the doped samples. The resistances of the samples were seen to be suppressed in lower doping range, which can be attributed to the more electropositive character of inorganic alkali cations. A prominent blue shift has seen in the steady state photoluminescence and optical absorption spectra with higher alkali cation doping, which corresponds to increase in the energy bandgap and this effect is very small in light doped samples. The x-ray photoemission spectroscopy studies of all the investigated perovskite samples have shown the presence of Pb+2 and I-1 oxidation states. The intercalation of inadvertent carbon and oxygen in perovskite films was also investigated by x-ray photoemission spectroscopy. It is observed that the respective peaks intensities of carbon and oxygen, responsible for methylammonium lead iodide decomposition has decreased with partial doping, which can be attributed to the doping of oxidation stable alkali metal cations (K+1, Rb+1, Cs+1). Following this work, some of the properties of the phase pure organicinorganic MAPbI3 have been studied. The selected devices with pristine as well as doped perovskite i.e., (MA)1-xBxPbI3 (B= K, Rb, Cs) based inverted perovskite photovoltaic cells were fabricated and tested their power conversion efficiencies. Later, the power conversion characteristics of the devices were investigated by developing an electronic circuit allowing versatile power point tracking of solar devices. The device with the best efficiency of 15.37% was attained with 30% Cs doping, having device parameters as; open circuit voltage value of 1.08V, photocurrent density (Jsc) of 19.70mA/cm2, and fill factor of 0.72. In case of potassium (K+) based mixed cation perovskite based devices, efficiency of about 13.32% is obtained with 10% doping. Using this approach, the stability of the materials and performances of perovskite based solar devices have been increased. These studies showed that the organic (MA) and inorganic cations (K, Rb and Cs) can be used in specific ratios by wet chemical synthesis procedure for better stability and efficiency of solar cells. We showed that mixed cations lead to a stable perovskite tetragonal phase in low atomic concentrations with no appreciable variation in energy bandgap of the photo-absorber, allowing the material to intact with the properties of un-doped perovskite with enhanced efficiency and stability.